ABS / Rear Wheel Sensor problems 2004 R1150RS

[1150RSSSS]

I've had a recurring problem with my ABS (2004 R1150RS), and while I've made some progress diagnosing the problem, I'm not there yet and would appreciate some advice before moving on to the next level of diagnostics...

ABS was not working on the rear wheel, coming and going along with the flashing lights (1hz). This evolved into no power to the rear brake (flashing 4hz). I got a fault code reader and it indicated rear wheel sensor and rear brake switch. I've managed to correct the rear brake "switch" problem (new bulbs, new fuses, returned the lights to stock and soldered wires together that had been botched by a bad aftermarket arrangement, new battery), but am now back to the rear wheel sensor problem. I have power (servo working) but no ABS. 

Here's what I've done - replaced the sensor with a used one, checked the gap, checked for dirt and damage to the ring, checked the wiring that I can see. I am presuming the ABS unit itself is fine as I would be getting different fault codes (and it did at one point resume working on its own for nearly a whole riding season before failing again). The brake fluid was changed when the problem started but this did not fix the issue. Brake fluid levels still all good. 

I think the next step is to remove the tank and look at the wiring, particularly where the rear wheel sensor connects (if visible). I have seen in a diagram of an ABS electronic control board that one of the pins (#36) related to the Rear ABS Sensor is also related to the rear fluid level. I am NOT an electrical engineer, but it got me wondering if the sensor fault might be related to a fluid level problem (although I believe there is a distinct fault code for that...). 

Any advice on how to proceed and what else to look for or try would be most WELCOME!

Thanks in advance, and MANY thanks to other posts on this forum that have gotten me this far!

[dirtrider]

17 minutes ago, 1150RSSSS said:

I've had a recurring problem with my ABS (2004 R1150RS), and while I've made some progress diagnosing the problem, I'm not there yet and would appreciate some advice before moving on to the next level of diagnostics...

ABS was not working on the rear wheel, coming and going along with the flashing lights (1hz). This evolved into no power to the rear brake (flashing 4hz). I got a fault code reader and it indicated rear wheel sensor and rear brake switch. I've managed to correct the rear brake "switch" problem (new bulbs, new fuses, returned the lights to stock and soldered wires together that had been botched by a bad aftermarket arrangement, new battery), but am now back to the rear wheel sensor problem. I have power (servo working) but no ABS. 

Here's what I've done - replaced the sensor with a used one, checked the gap, checked for dirt and damage to the ring, checked the wiring that I can see. I am presuming the ABS unit itself is fine as I would be getting different fault codes (and it did at one point resume working on its own for nearly a whole riding season before failing again). The brake fluid was changed when the problem started but this did not fix the issue. Brake fluid levels still all good. 

I think the next step is to remove the tank and look at the wiring, particularly where the rear wheel sensor connects (if visible). I have seen in a diagram of an ABS electronic control board that one of the pins (#36) related to the Rear ABS Sensor is also related to the rear fluid level. I am NOT an electrical engineer, but it got me wondering if the sensor fault might be related to a fluid level problem (although I believe there is a distinct fault code for that...). 

Any advice on how to proceed and what else to look for or try would be most WELCOME!

Thanks in advance, and MANY thanks to other posts on this forum that have gotten me this far!

Afternoon  1150RSSSS

 

You have  a LOT going on there so nothing "just happened" to look for.

 

My first concern is:  ARE YOU CHASING THE RIGHT MALFUNCTION? 

 

What code reader are you using & is it giving you the correct fault code????????????????????????

 

I have worked with a few riders over the last couple of years that have sent me I-ABS fault codes that were not the correct fault code for the actual failure event they were supposedly chasing. 

 

So, first thing, make darn sure that your code reader is giving you the correct failure code or codes (check them against a real GS-911).

 

If you are pretty darn sure that you are chasing the correct failure code or codes then ohm out the front & rear wheel speed sensors, then compare the numbers (they should be pretty close to the same).

 

Also check the rear speed sensor harness connector & terminals for a damaged wire as that has been a problem on some over the years. 

 

You can also ohm the speed sensor circuits out at the unplugged ABS module connector.  If they ohm out as OK then that alone tells you something about the integrity of the connections. 

[1150RSSSS]

Thanks for the prompt reply. I'm definitely not sure I'm chasing the right problem (!), but I've read that the ABS system is very sensitive to even minor fluctuations in voltage, and the on and off nature of the issue has led me to assume (hope?) that the problem is electrical in nature.

I'm using a motoscan code reader, and the fault simply says "rear wheel speed sensor."  The other fault, which is now gone was "brake light switch, rear." I've read that the GS911 is better (and more expensive). Is it possible that it might give me a completely different fault, or more detailed info about the same fault? And I noticed that the cheaper yellow/orange gs911 has been discontinued by Hex (although still on its website), but is available through some other online retailers. Is this model as good as the others? Unclear...

I've checked the wire harnesses for visible damage and can see none (though the two wires that come off the connecter up near the seat look REALLY thin and vulnerable). Would this typical damage be visible on the rear half of the bike, or under the tank at the ABS module?

Based on your advice, it seems the easiest and cheapest next step would be to  remove the tank and ohm out the front and rear sensors as you suggest and look for other issues like oxidation at the connections. Would appreciate any other advice about what I might do or look for when I'm there.

Grateful!

 

[dirtrider]

6 minutes ago, 1150RSSSS said:

Thanks for the prompt reply. I'm definitely not sure I'm chasing the right problem (!), but I've read that the ABS system is very sensitive to even minor fluctuations in voltage, and the on and off nature of the issue has led me to assume (hope?) that the problem is electrical in nature.

I'm using a motoscan code reader, and the fault simply says "rear wheel speed sensor."  The other fault, which is now gone was "brake light switch, rear." I've read that the GS911 is better (and more expensive). Is it possible that it might give me a completely different fault, or more detailed info about the same fault? And I noticed that the cheaper yellow/orange gs911 has been discontinued by Hex (although still on its website), but is available through some other online retailers. Is this model as good as the others? Unclear...

I've checked the wire harnesses for visible damage and can see none (though the two wires that come off the connecter up near the seat look REALLY thin and vulnerable). Would this typical damage be visible on the rear half of the bike, or under the tank at the ABS module?

Based on your advice, it seems the easiest and cheapest next step would be to  remove the tank and ohm out the front and rear sensors as you suggest and look for other issues like oxidation at the connections. Would appreciate any other advice about what I might do or look for when I'm there.

Grateful!

 

Evening  1150RSSSS

 

The Motoscan code reader is one that I received incorrect codes from. Now I wasn't the one using the Motoscan so all I have to go on is the incorrect fault codes that were sent to me.   

 

Based on your advice, it seems the easiest and cheapest next step would be to  remove the tank and ohm out the front and rear sensors--  This would probably be my next move just to eliminate the sensor or wire resistance as the problem. 

[1150RSSSS]

Good afternoon Dirtrider - Quick update: I took off the tank, but the pin-holes at the ABS connection look so small and delicate I shied away from attempting an ohm test. This is new territory for me mechanically, (compelled by necessity and not for pleasure) and I didn't want to damage anything and probably wouldn't trust any results that I could obtain. I did observe that all the pins at the ABS were very clean.

The rear brake servo is now out again, intermittently (brake warning light on, abs flashing 4hz, rear brake light not activated by the ). I thought I had "fixed" that problem with all the other fuse cleaning and replacement, bulb replacement, etc. but its back (it happened a couple of times before I took the tank off, and is now intermittent again, so I don't think it is related to the tank removal). 

I inspected the rear brake light and rear sensor connections to the wire harness, cleaned as much as I could with electrical spray cleaner, but no change. I did notice that when I jiggled the brake light line, it interrupted the flashing lights before they resumed with the fault flashing. The closest I have come to a cause and effect moment!

To rule it out, I am inclined to replace those connections, as the parts are not that expensive, and they are easy to access, just to rule it out, and something I probably would have tried first anyway had I obtained a trustworthy ohm reading indicating some additional resistance. They appear to be quite vulnerable where they are located, subject to vibration and the elements. Welcoming any additional wisdom on the matter and VERY grateful for your help.

[dirtrider]

9 minutes ago, 1150RSSSS said:

Good afternoon Dirtrider - Quick update: I took off the tank, but the pin-holes at the ABS connection look so small and delicate I shied away from attempting an ohm test. This is new territory for me mechanically, (compelled by necessity and not for pleasure) and I didn't want to damage anything and probably wouldn't trust any results that I could obtain. I did observe that all the pins at the ABS were very clean.

The rear brake servo is now out again, intermittently (brake warning light on, abs flashing 4hz, rear brake light not activated by the ). I thought I had "fixed" that problem with all the other fuse cleaning and replacement, bulb replacement, etc. but its back (it happened a couple of times before I took the tank off, and is now intermittent again, so I don't think it is related to the tank removal). 

I inspected the rear brake light and rear sensor connections to the wire harness, cleaned as much as I could with electrical spray cleaner, but no change. I did notice that when I jiggled the brake light line, it interrupted the flashing lights before they resumed with the fault flashing. The closest I have come to a cause and effect moment!

To rule it out, I am inclined to replace those connections, as the parts are not that expensive, and they are easy to access, just to rule it out, and something I probably would have tried first anyway had I obtained a trustworthy ohm reading indicating some additional resistance. They appear to be quite vulnerable where they are located, subject to vibration and the elements. Welcoming any additional wisdom on the matter and VERY grateful for your help.

Afternoon 1150RSSSS

 

The rear brake servo is now out again-- If the rear servo is malfunctioning then that is usually an internal ABS module problem (like an internal pressure switch).

 

Things like brake light wiring or rear brake light bulb will not cause a servo malfunction, just an illuminated dash warning light. 

 

Even a wheel sensor problem should not cause a servo malfunction (just no ABS available & a dash warning)

 

A faulty brake light switch, or incorrectly adjusted brake light switch can cause a servo not to operate (not always but can).

 

You need to start a  detailed list on EXACTY what does & doesn't work when the problem happens (everything needs to be checked for function) .  We can then try to match ALL the existing symptoms up to the possible causes. 

 

  

[1150RSSSS]

Thanks Dirtrider. Here is the most complete list I have. There are 2 "states" of malfunction, and the bike randomly alternates between the two, almost always in between startups but only once while riding (I think).

State 1:

Warning light on, abs light flashes quickly at start up and then settles into 1hz. Warning light and 1hz flashing remain while riding. Front and rear brake servo works, rear tail light is activated by rear brake switch, but no abs at the rear. I have not tested the front abs in this condition (but will do so when possible). Motoscan (for what it's worth, but it's all I've got right now) indicates a rear wheel sensor problem. Note: This problem first occurred a couple of seasons ago, then disappeared entirely for the next riding season, only to return again. After it first occurred, the brakes were bled, and the problem very "temporarily" resolved but then returned, on and off again. And as a reminder, the sensor was replaced with a used one, gap checked, to no effect.

State 2: 

Warning light on, abs flashes quickly at startup and then stays there. Warning light and 4hz flashing remain while riding. No servo power to rear brake, rear tail light is not activated by rear brake switch. Front brake has servo power, but (I just tested) has no abs. Motoscan (caveats again...) indicates a problem with the rear brake light switch and a rear wheel sensor problem. When the bike (seemingly randomly) reverts to State 1, I can clear the brake switch fault code with Motoscan and only the sensor error remains. Note: this problem first appeared last September, at the end of the problem-free riding season, and then disappeared for several months, only to return this spring. 

One potentially important bit of info - the rear tail light was reconfigured by the first owner, with an additional LED brake light and the turn signal lights configured to always be illuminated. They had done a hack job of it, left wires connected with wire nuts, etc. so I reinstalled the stock configuration with OEM parts, soldered wires back together, replaced all bulbs etc. It was something I had been meaning to do anyways and thought at least it might help rule out some miscellaneous issue that might be contributing to the problem. It appeared at first that it got me from State 2 back to State 1, and I was hopeful, but State 2 is back...

Two questions - if it is an internal abs module problem, such as an internal pressure switch as you suggest, would it come and go in this fashion or would it just fail? And if it might be a rear brake switch faulty for some reason (hope springs eternal...), I'm presuming that might result in a failure to initialize at startup?

Very appreciative of your time and expertise!

 

[dirtrider]

Morning 1150RSSSS

 

  

State 1:

 

Warning light on, abs light flashes quickly at start up and then settles into 1hz. Warning light and 1hz flashing remain while riding. --- This is just indicating no  ABS available  (could be due to bad wheel speed sensor), or some other internal ABS module problem. 

 

Front and rear brake servo works, rear tail light is activated by rear brake switch, but no abs at the rear. I have not tested the front abs in this condition (but will do so when possible).-- This would fit with a rear wheel speed sensor malfunction, or open in the rear wheel speed  sensor wiring. Can't eliminate an internal problem with ABS module but USUALLY external like wheel speed sensor signal not getting to ABS module. 

 

Motoscan (for what it's worth, but it's all I've got right now) indicates a rear wheel sensor problem.-- I don't totally trust the Motoscan  but that does fit the above problem. If it is a legitimate malfunction code then it might be a sensor problem, or a wiring problem, or in how the ABS module processes the speed signal.

 

Note: This problem first occurred a couple of seasons ago, then disappeared entirely for the next riding season, only to return again. After it first occurred, the brakes were bled, and the problem very "temporarily" resolved but then returned, on and off again. And as a reminder, the sensor was replaced with a used one, gap checked, to no effect.-- This is good to know but not enough info in it to really help much. 

 

If I was working on this with the limited info above I would start by testing the resistance & AC voltage output of both the front & rear wheel speed sensors at the unplugged ABS module connector. Then compare front to rear resistance & AC voltage. 

 

 

[dirtrider]

State 2: 

 

Warning light on, abs flashes quickly at startup and then stays there. Warning light and 4hz flashing remain while riding. No servo power to rear brake, rear tail light is not activated by rear brake switch.-- This indicates one end in residual braking (no servo assist). This could be due to any number of things but rear wheel speed sensor is usually not one of them. This could be an internal pressure switch. 

 

Front brake has servo power, but (I just tested) has no abs.-- If one of the servos is not working then you usually can't have ABS available. 

 

Motoscan (caveats again...) indicates a problem with the rear brake light switch and a rear wheel sensor problem. When the bike (seemingly randomly) reverts to State 1, I can clear the brake switch fault code with Motoscan and only the sensor error remains. Note: this problem first appeared last September, at the end of the problem-free riding season, and then disappeared for several months, only to return this spring. -- You need to check/test the rear brake switch just to eliminate an external issue. The brake switch is N/C (closed) & goes open at brake apply (reverse logic). Test it a number of times & also make sure that the rear brake pedal fully, easily, & completely returns. An improperly operating rear brake switch can cause issues depending on when the ABS module sees the failure. If the switch operation tests out OK maybe try lifting the rear brake pedal with your foot (or not even using it) before initial ride off.   

 

 

One potentially important bit of info - the rear tail light was reconfigured by the first owner, with an additional LED brake light and the turn signal lights configured to always be illuminated. They had done a hack job of it, left wires connected with wire nuts, etc. so I reinstalled the stock configuration with OEM parts, soldered wires back together, replaced all bulbs etc. It was something I had been meaning to do anyways and thought at least it might help rule out some miscellaneous issue that might be contributing to the problem. It appeared at first that it got me from State 2 back to State 1, and I was hopeful, but State 2 is back...-- This wiring can cause a dash warning light but typically doesn't effect either servo or ABS operation.

 

 

Two questions - if it is an internal abs module problem, such as an internal pressure switch as you suggest, would it come and go in this fashion or would it just fail?-- Typically they just fail but I have seen this be an intermittent problem at times. 

 

And if it might be a rear brake switch faulty for some reason (hope springs eternal...), I'm presuming that might result in a failure to initialize at startup?-- Possible, but a failed rear brake switch is usually no worse that starting with the rear brake applied.  It tends to be more of a problem at or after ride-off. As a test try unplugging the rear brake switch then shorting the chassis side terminals together with a jumper wire (then ride motorcycle without touching or using the rear brake pedal  (see if anything changes). 

 

There is an option to completely remove the  ABS & servo system, that leaves very nice conventional braking system  (Actually feels better than the servo assist system) but obviously no ABS available. Depending on how you feel about having an ABS system this is a well accepted option on older BMW 1150 bikes. 

 

It needs a relay added for brake light function (use the existing ABS warning relay from  the fuse box). Use the existing front brake hoses & lines so nothing extra needed there. Can use the existing rear brake hose with some work.

[1150RSSSS]

Many thanks Dirtrider. Appreciate your analysis - I have more work to do!

[1150RSSSS]

Thanks again Dirtrider. I've done some additional investigation based on your advice. Here's what I've learned:

Rear speed sensor:

-I ohm tested the front and rear speed sensors, both through the ABS module (approx. 230 ohms both front and rear) as well as the individual connections to the ABS module. Re the individual lines, they were all showing <1 ohm except the black and white wire from the rear which was showing +100 ohms (I retested to confirm). Maybe something going on there...

Rear Brake:

-The rear brake switch works perfectly (<1ohm when open, and no current when pedal depressed).

-Shorted out the chassis side brake rear brake wires but no change with faults, operation, etc.

-I tested the individual rear brake wires connecting the switch to the ABS module, and both were approx. 1.5 ohms.

-I tested the whole loop of the rear brakes through the ABS module and got 1.9 K ohms. Not sure how to interpret this reading, as the inner workings of the ABS module are a mystery to me, but certainly higher than the speed sensors which also run through the module (and, as I've mentioned before, this is my first rodeo on diagnostics of this kind).

I have not been able to get to the front brake switch. It's way up "there," even with the tank off, mounted to a plastic thing that secures a bunch of couplings, bolted at the bottom (easy to reach) and top (not so easy). If you think a front brake switch reading would be valuable, I'd welcome any advice on how to reach it.

Leaving the tank off for now and grateful for any advice!

[dirtrider]

Afternoon 1150RSSSS

 

Quote

-I ohm tested the front and rear speed sensors, both through the ABS module (approx. 230 ohms both front and rear) as well as the individual connections to the ABS module. Re the individual lines, they were all showing <1 ohm except the black and white wire from the rear which was showing +100 ohms (I retested to confirm). Maybe something going on there...

Can you explained how you tested  "through the ABS module", I don't quite understand this procedure?

 

 

Quote

-The rear brake switch works perfectly (<1ohm when open, and no current when pedal depressed).

Good

 

Quote

-Shorted out the chassis side brake rear brake wires but no change with faults, operation, etc.

 Good

 

Quote

-I tested the individual rear brake wires connecting the switch to the ABS module, and both were approx. 1.5 ohms.

Sounds OK

 

Quote

-I tested the whole loop of the rear brakes through the ABS module and got 1.9 K ohms. Not sure how to interpret this reading, as the inner workings of the ABS module are a mystery to me, but certainly higher than the speed sensors which also run through the module (and, as I've mentioned before, this is my first rodeo on diagnostics of this kind).

You need to further explain testing "THROUGH" The ABS module?

 

Quote

I have not been able to get to the front brake switch. It's way up "there," even with the tank off, mounted to a plastic thing that secure
s a bunch of couplings, bolted at the bottom (easy to reach) and top (not so easy). If you think a front brake switch reading would be valuable, I'd welcome any advice on how to reach it.

Just test at the front brake switch pigtail connector to the chassis harness (follow the wire from the switch to the connector)

[1150RSSSS]

Thanks D.R.  - your question has prompted me to further evaluate what I meant by "through" and I've since learned that what I was testing would not have yielded anything meaningful.

I think at this point the only real information I've gathered is that one of the wires from the rear sensor to the pin connection at the ABS module is disconnected somewhere (no continuity), the other rear wire and both of the front sensor wires are all showing less than 1 ohm of resistance. 

As far as the rear brake, the switch at the pedal is good, and both wires from the pigtail to the ABS module are also apparently good (showing 1.5 ohms). 

My guess at the moment is that the sensor issue might be fixable if I re-wire from the pigtail to the ABS module (possibly worth a try).

But, the real problem keeping me from riding is the total lack of servo power to the rear, which I had hoped was an electrical connection external to the ABS module but now seems to be based on some internal malfunction. If there are other diagnostics I can do to confirm my read of the situation, I would appreciate any suggestions.

If it is internal, as you suspected earlier in this thread, I suppose my options are to rebuild the module (there's a place in Germany that can do this) or opt for an ABS-ectomy?

Grateful for your advice!

[dirtrider]

 

 

Evening  1150RSSSS

 

 

Quote

I think at this point the only real information I've gathered is that one of the wires from the rear sensor to the pin connection at the ABS module is disconnected somewhere (no continuity), the other rear wire and both of the front sensor wires are all showing less than 1 ohm of resistance. 

Yes, an open wire sure could case a problem-- Repair THAT problem then see where you are at.

 

Quote

My guess at the moment is that the sensor issue might be fixable if I re-wire from the pigtail to the ABS module (possibly worth a try).

That is definitely where I would start. 

 

 

Quote

But, the real problem keeping me from riding is the total lack of servo power to the rear, which I had hoped was an electrical connection external to the ABS module but now seems to be based on some internal malfunction. If there are other diagnostics I can do to confirm my read of the situation, I would appreciate any suggestions.

Do you have access to a GS-911? If so grabbing the fault codes can be a BIG help.  

Quote

 

If it is internal, as you suspected earlier in this thread, I suppose my options are to rebuild the module (there's a place in Germany that can do this) or opt for an ABS-ectomy?

Grateful for your advice!

 

My personal favorite is to just remove the ABS system as that leaves great feeling conventional brakes. If you can live without ABS then that is an option. 

Quote

 

[cat0020]

I removed the servo assist ABS on my 2002 R1150RS back in the winter of 2018. 

 

No more abrupt braking at parking lot speed, no more excess electrical draw stopped at traffic light or prior to engine start, lost about 6-8 lb. of dead weight at fuel tank level of the bike. 

 

I prefer non-ABS braking anyway, all pluses for me when I removed the servo-ABS pump and changed out the near 20 y-o brake hoses. 

 

 

[1150RSSSS]

Thanks DR and cat0020. If you remove the ABS and servo-assist, are the brakes then equivalent to what I'm experiencing now with my dysfunctional rear servo (which is about 20% of normal)? Or is there some aspect to the procedure / bypass that will make them work like good manual brakes? I've read a lot about the procedure, and watched way too many videos about it,  but this aspect has always confused me...

[dirtrider]

34 minutes ago, 1150RSSSS said:

Thanks DR and cat0020. If you remove the ABS and servo-assist, are the brakes then equivalent to what I'm experiencing now with my dysfunctional rear servo (which is about 20% of normal)? Or is there some aspect to the procedure / bypass that will make them work like good manual brakes? I've read a lot about the procedure, and watched way too many videos about it,  but this aspect has always confused me...

Morning 1150RSSSS

 

NO, your brakes will be WAY/WAY better than your present ABS system in residual mode. It will also be less grabby than your present system with power assist active.

 

Trust me, you will like the brake FEEL better than your present system even with power assist working. 

 

When you remove the servo ABS system you make a trade-off. You gain better feeling easier to modulate conventional braking (feeling just like most OEM motorcycles with no ABS system). 

 

But the trade-off is that you have no ABS available. 

 

I have yet to talk to anyone owning a BMW 1150 that  was not happier with their brakes after removing the ABS system. But some say they miss having ABS to save their butt but would still make the removal choice due to better feeing brake modulation.    

[RogerC60]

I'll add in a note about rear pads that dirtrider made a while back. After I removed the ABS on my '03 RT the rear brake was much stronger than before, so much so that I found it too easy to lock up the rear wheel. Dirtrider suggested switching over to organic pads in the rear and it made a huge difference. I really really like my brakes now.

[1150RSSSS]

Really great advice, thanks all around. Having analyzed everything external to the ABS module (with excellent guidance from Dirtrider), I'm pretty convinced that the rear servo failure is internal and I've decided to remove the module rather than rebuild (for anyone looking for a rebuild, these guys appear to be the only ones doing it: https://rhelectronics.de/. If my math is correct, about $1300 or more all in). While I always liked the idea of ABS, having ridden without it for 20+ years, I'm comfortable without it, especially if I have better brake feel. Thanks again for all the advice.

 

[1150RSSSS]

One more quick follow on (if I may)...

There seem to be at least two ways to re-wire:

1. change the brake switches to a non-ABS configuration (no current when at rest), and cut the main harness at the ABS pin connection and reconnect the appropriate wires.

2. Do not change the brake switches, and keep the wires going into the ABS module but disconnect the control module from the ABS itself.

(there's a third way involving the re-use of the no-longer-needed ABS relay from the fuse box, but I've heard mixed reviews on this way).

Any thoughts on which way is best?

[dirtrider]

12 minutes ago, 1150RSSSS said:

One more quick follow on (if I may)...

There seem to be at least two ways to re-wire:

1. change the brake switches to a non-ABS configuration (no current when at rest), and cut the main harness at the ABS pin connection and reconnect the appropriate wires.

2. Do not change the brake switches, and keep the wires going into the ABS module but disconnect the control module from the ABS itself.

(there's a third way involving the re-use of the no-longer-needed ABS relay from the fuse box, but I've heard mixed reviews on this way).

Any thoughts on which way is best?

Afternoon 1150RSSSS

 

 

Quote

 

There seems to be at least two ways to re-wire:

1. change the brake switches to a non-ABS configuration (no current when at rest), and cut the main harness at the ABS pin connection and reconnect the appropriate wires.

 

You can change the brake switches if you want to but you don't gain much as you STILL have to re-wire at the ABS module. 

 

Quote

2. Do not change the brake switches, and keep the wires going into the ABS module but disconnect the control module from the ABS itself.

You can do that (remove then use the ABS black box, that takes making a close-out cover for the removed ABS black box. Plus you have to get-to then-remove one of the ABS lights from the dash a (pain). 

 

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(there's a third way involving the re-use of the no-longer-needed ABS relay from the fuse box, but I've heard mixed reviews on this way).

This is usually how I do it as you need to remove the relay anyhow, it also gets rid of the the clutter & puts both lights out.   

 

Quote

Any thoughts on which way is best?

Whatever you are comfortable with. Some keep the ABS module black box, others just use the removed relay. I use the removed relay, splice the needed wires just before the ABS module plug,  (then waterproof the plug), then use a male/female connector on my added wires  so my ABS relay/brake light _tail light system can just unplug, then a working, or repaired, ABS module can easily be reinstalled at a later time if wanted.

[1150RSSSS]

Thanks again for all the advice. The ABS-ectomy is happening next Tuesday. In the meantime, having removed the gas tank several times during my explorations I've damaged the o-ring on the gas disconnect (rookie mistake). I understand the fix in the future is to lubricate it prior to reassembly. Any suggestions on the proper lubricant to use where gas may be present? thanks

 

[dirtrider]

2 minutes ago, 1150RSSSS said:

Thanks again for all the advice. The ABS-ectomy is happening next Tuesday. In the meantime, having removed the gas tank several times during my explorations I've damaged the o-ring on the gas disconnect (rookie mistake). I understand the fix in the future is to lubricate it prior to reassembly. Any suggestions on the proper lubricant to use where gas may be present? thanks

 

Afternoon  1150RSSSS

 

A little lube does help but the main cause of "O" ring damage is in not holding the release trigger down when sliding the connector together.

 

I usually use about anything handy, grease motor oil, assembly lube, gasoline, etc. Just use very little of anything. 

[1150RSSSS]

perfect thanks!

[cat0020]

The fuel lines on these oilheads are pressurized, nearly 20 y-o fuel lines may need update anyway. 

I changed out my fuel lines and couplings back in 2019 to these stainless steel units to replace the OEM plastic ones: 

[1150RSSSS]

Thanks and yes I'm aware of the problem (it ruined a trip for a friend of mine). Mine were replaced with metal before I bought the bike.

[1150RSSSS]

Following up-

The ABS removal was a success – thanks all for the advice and assistance. Brakes are working well, with nice feel, and the running lights and front brake light are working as intended. My one lingering problem is the rear brake light, which is not working. I can confirm that there is a 100% connection between the rear switch and the newly configured relay, so now I’m wondering if I’ve used the wrong wiring method around the repurposed relay (I chose the method which retains the existing brake switches and uses the existing ABS relay for re-wiring and to extinguish the warning lights.) My method was taken from an older thread on another site and listed as general instructions for the R1150 IABS systems and is as follows:

1) Remove the blue ABS relay from the fusebox. This will extinguish the 'Brake Failure' warning light on the dash and as a bonus can be used to operate the brake light !! (no need for new switches as in other methods )
2) Strip back the sheathing from the ABS multi pin connector - identify wires and connect as follows
a) Grey/White wire (tail light feed) Grey/Black wire (12v feed) cut both and join together - thats your tail light sorted.
b) White/Yellow wire (front brake switch) and Yellow/Green wire (rear brake switch). Cut these two wires and join them to link brake switches
Now the wiring to the redundant 4 pin ABS relay
c) Pin 1 - Connect white/blue wire
d) Pin 2 - connect the THIN solid brown wire in the loom to provide a ground ( careful here - there are several brown wires c/w coloured traces and a Thick brown wire)
e) Pin 3 - Find the Yellow/Black wire and the solid green wire. Cut and connect these together and then to pin 3 of the relay
f) Pin 4 - Connect grey/yellow (tail light feed) to this pin

I do know this method generally has met with success, but I’m not sure if this particular wiring is specific to a GS, RT, R or other model, and maybe it’s different for the RS I have? I have been working with a very experienced independent BMW mechanic on this and he was confused by this configuration but was unable to determine an immediate fix (he has done servo-ectomies in the past but using the method that replaces the brake switches).

As always, I welcome any advice and am grateful for the help.

[dirtrider]

19 hours ago, 1150RSSSS said:

Following up-

The ABS removal was a success – thanks all for the advice and assistance. Brakes are working well, with nice feel, and the running lights and front brake light are working as intended. My one lingering problem is the rear brake light, which is not working. I can confirm that there is a 100% connection between the rear switch and the newly configured relay, so now I’m wondering if I’ve used the wrong wiring method around the repurposed relay (I chose the method which retains the existing brake switches and uses the existing ABS relay for re-wiring and to extinguish the warning lights.) My method was taken from an older thread on another site and listed as general instructions for the R1150 IABS systems and is as follows:

1) Remove the blue ABS relay from the fusebox. This will extinguish the 'Brake Failure' warning light on the dash and as a bonus can be used to operate the brake light !! (no need for new switches as in other methods )
2) Strip back the sheathing from the ABS multi pin connector - identify wires and connect as follows
a) Grey/White wire (tail light feed) Grey/Black wire (12v feed) cut both and join together - thats your tail light sorted.
b) White/Yellow wire (front brake switch) and Yellow/Green wire (rear brake switch). Cut these two wires and join them to link brake switches
Now the wiring to the redundant 4 pin ABS relay
c) Pin 1 - Connect white/blue wire
d) Pin 2 - connect the THIN solid brown wire in the loom to provide a ground ( careful here - there are several brown wires c/w coloured traces and a Thick brown wire)
e) Pin 3 - Find the Yellow/Black wire and the solid green wire. Cut and connect these together and then to pin 3 of the relay
f) Pin 4 - Connect grey/yellow (tail light feed) to this pin

I do know this method generally has met with success, but I’m not sure if this particular wiring is specific to a GS, RT, R or other model, and maybe it’s different for the RS I have? I have been working with a very experienced independent BMW mechanic on this and he was confused by this configuration but was unable to determine an immediate fix (he has done servo-ectomies in the past but using the method that replaces the brake switches).

As always, I welcome any advice and am grateful for the help.

Afternoon   1150RSSSS

 

You are probably going to need a different relay, your brake switches are N/C that  go open with lever or pedal apply so you need a relay  that has N/C  contacts & goes OPEN with power across the pull-in coil (usually a 5 pin relay).

 

Have your tec put an ohmmeter on that blue relay between pins 3 & 4, if it is open with no power applied to pins 1 & 2 then that relay won't work. 

 

Go grab a 5 pin  relay from you local auto parts store that has pins 85, 86, 30, 87 & 87A. The 85 & 86 are the pull-in coil & the 30 is B+, 87 & 87a are the B+ out.

 

  

[1150RSSSS]

Thank you Dirtrider. I tested the relay and it seems that 3&4 are closed with no voltage applied to 1&2, so I believe it is the right relay. What's confusing is that the front brake light works properly (relay clicks), but the rear does not, even though the front and rear are wired in serial (which seems to make sense, as a break in voltage from either switch would activate the lights through the relay). I've tested the brake switch itself (many times) and it works perfectly. I've dug deeper into the threads where I got the re-wiring instructions, but could not find any troubleshooting discussion relative to my particular outcome. The method seems to have worked for many others, so I'm not sure if there is something unique to the RS wiring (v GS for instance).

So close and yet so far!

[dirtrider]

33 minutes ago, 1150RSSSS said:

Thank you Dirtrider. I tested the relay and it seems that 3&4 are closed with no voltage applied to 1&2, so I believe it is the right relay. What's confusing is that the front brake light works properly (relay clicks), but the rear does not, even though the front and rear are wired in serial (which seems to make sense, as a break in voltage from either switch would activate the lights through the relay). I've tested the brake switch itself (many times) and it works perfectly. I've dug deeper into the threads where I got the re-wiring instructions, but could not find any troubleshooting discussion relative to my particular outcome. The method seems to have worked for many others, so I'm not sure if there is something unique to the RS wiring (v GS for instance).

So close and yet so far!

Morning  1150RSSSS

 

OK, that makes it easier to diagnose. 

 

Your brake light switch's need to be wired is series to work properly. (IE a big continuous loop)

 

Seeing as the brake light works from the front brake switch that means that it (is) working  correctly & the relay is functioning properly.

 

So with the key ON just unplug the rear brake switch, if the brake light comes on (stays on)  then it is wired correctly. If the brake light doesn't come on then  you have the rear brake switch wired into the relay brake-switch-circuit incorrectly. 

 

Try unplugging the rear brake switch then post back with the results,   if unplugging the rear switch  doesn't illuminate the brake light then I will have to dig out my old 1150RS wire diagrams then  plot what you DID vs what is NEEDED. 

[1150RSSSS]

Many thanks - I will perform the test you prescribe. In the meantime, I'm attaching a "cheat sheet" of how it is currently wired FYI.

[dirtrider]

8 minutes ago, 1150RSSSS said:

Many thanks - I will perform the test you prescribe. In the meantime, I'm attaching a "cheat sheet" of how it is currently wired FYI.

Morning  1150RSSSS

 

If you have it wired as shown then is should work (unplugging rear brake switch should verify this).

 

If unplugging the rear brake switch doesn't bring the brake light on then it isn't wired as shown. (so re-check wires colors & use an ohmmeter to verify continuity of brake switches in series)

[1150RSSSS]

Thanks again Dirtrider. The plot thickens...

-Double checked all wire colors and connections: all good, wired as drawn.

-Disconnected the direct connection between betw/ front and rear brake switch (W/Y - Y/G), brake light stays on as expected: all good

-Disconnected the rear brake (Y/Black) from pin 3, and the front brake STILL works when lever is depressed (which is very confusing, because the loop is broken so I would expect the brake light to be stuck on): very strange! (Works the same when rear brake is connected to pin 3).

-As a test, I also disconnected the green wire from the ignition from pin 3 as well and I get no brake light at all, which is what I would expect.

-Ohm tested front and rear brake switches individually at these connections and they are still all good - closed at rest and open (completely) when levers depressed. 

-I get the same result when I test them in series from one end to the other.

Needless to say, these results are pretty confusing! 

Once again, grateful for any suggestions.

 

 

 

[dirtrider]

11 hours ago, 1150RSSSS said:

Thanks again Dirtrider. The plot thickens...

-Double checked all wire colors and connections: all good, wired as drawn.

-Disconnected the direct connection between betw/ front and rear brake switch (W/Y - Y/G), brake light stays on as expected: all good

-Disconnected the rear brake (Y/Black) from pin 3, and the front brake STILL works when lever is depressed (which is very confusing, because the loop is broken so I would expect the brake light to be stuck on): very strange! (Works the same when rear brake is connected to pin 3).

-As a test, I also disconnected the green wire from the ignition from pin 3 as well and I get no brake light at all, which is what I would expect.

-Ohm tested front and rear brake switches individually at these connections and they are still all good - closed at rest and open (completely) when levers depressed. 

-I get the same result when I test them in series from one end to the other.

Needless to say, these results are pretty confusing! 

Once again, grateful for any suggestions.

Morning  1150RSSSS

 

-Double checked all wire colors and connections: all good, wired as drawn.-- This is a good first step.

 

-Disconnected the direct connection between between/ front and rear brake switch (W/Y - Y/G), brake light stays on as expected: all good-- Good so far.

 

-Disconnected the rear brake (Y/Black) from pin 3, and the front brake STILL works when lever is depressed (which is very confusing, because the loop is broken so I would expect the brake light to be stuck on): very strange! (Works the same when rear brake is connected to pin 3).-- Are you SURE the wires at the rear brake switch are the very same as you have hooked to the relay circuit????? It sort of seem that the rear brake circuit is either incorrect, or the rear brake switch wires are shorted (or pinched together or shorted to ground) at some place in their run. As a test try running temporary wires from the rear switch to the front brake switch loop.

 

-As a test, I also disconnected the green wire from the ignition from pin 3 as well and I get no brake light at all, which is what I would expect.-- This is good.

 

-Ohm tested front and rear brake switches individually at these connections and they are still all good - closed at rest and open (completely) when levers depressed. Again good test.

 

-I get the same result when I test them in series from one end to the other.-- Unplug from relay the test both wire for  short to GROUND. It's possible one of the rear brake light switch wires is shorted to ground (or shorted together).   

 

Needless to say, these results are pretty confusing!-- Not really confusing just still a problem to be found with persistence. 

[1150RSSSS]

Dirtrider - you've nailed it. It was a short in one of the rear brake switch wires. I did a temporary replace of those wires and it worked perfectly. I will replace those with a more permanent arrangement. It was something I missed in all my prior tests...its been a steep learning curve. In hindsight, the motoscan might have been pointing me in the right direction, but very happy at last to never have to worry about the ABS module or the trouble of bleeding it. I'm confused as to how the brake wire and the sensor wire both got frayed or damaged deep in the harness, but I guess things happen. Extremely grateful for your help and I'll make a later post summarizing what I've done for others who might encounter this problem (which may be more and more as this vintage of bike ages). 

Thank you again for your support and patience!

[dirtrider]

11 minutes ago, 1150RSSSS said:

Dirtrider - you've nailed it. It was a short in one of the rear brake switch wires. I did a temporary replace of those wires and it worked perfectly. I will replace those with a more permanent arrangement. It was something I missed in all my prior tests...its been a steep learning curve. In hindsight, the motoscan might have been pointing me in the right direction, but very happy at last to never have to worry about the ABS module or the trouble of bleeding it. I'm confused as to how the brake wire and the sensor wire both got frayed or damaged deep in the harness, but I guess things happen. Extremely grateful for your help and I'll make a later post summarizing what I've done for others who might encounter this problem (which may be more and more as this vintage of bike ages). 

Thank you again for your support and patience!

Afternoon  1150RSSSS

 

Glad you got is sorted. That is what the diagnostic info pointed to. 

 

Could be a wire pinched under a frame attachment, or a bolt/screw run into the harness, or even something spliced into that rear switch harness by a previous owner. (lots of ways to short a wire run) 

[Riccardo]

Hello Team. Is this discussion still “alive” please? I am new In this forum. Thank you. Riccardo

[dirtrider]

6 minutes ago, Riccardo said:

Hello Team. Is this discussion still “alive” please? I am new In this forum. Thank you. Riccardo

Afternoon  Riccardo

 

This thread is well over 1 year old & the OP's problem is already solved. 

 

If you have a new question or problem please start a new thread on your issue or question.

[1150RSSSS]

Welcome Riccardo - I will look for a new thread to offer any advice I can.