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Weird combination of dash light errors - R1100RT


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Hello all, hoping someone here can help with a weird and infuriating issue I have.


I have a '96 R1100RT, I believe UK-spec, of indeterminate mileage (speedo says 17k, MOTs from before I bought it suggest 70k+, things like the footpeg rubbers and side plates look brand new, all very confusing! Anyway, enough of that!)


Little bit of history first: Until late last year the bike was used fairly regularly and never gave me a moment's trouble, other than occasionally resetting the ABS if I let the battery get too low. Last autumn, I injured first one shoulder and then the other, so I didn't ride from about October until fairly recently. Also, the bike had to live outside last winter; it was usually covered over but this did get blown off and I wasn't able to drag it back on with my bad shoulders, but covered it when I could. I left it on a largish solar charger, but when I went back to it, the battery was completely dead, so I bought and fitted a new one. Then the fun starts…


The bike starts and runs fine, but there are problems in the dash. Ignition on, bike not running, the top ABS light flashes, and you can hear the relay operating. The bottom light is not on at all. The neutral light is NOT illuminated even though the bike is in neutral (this worked fine before, and the digital display shows 0). Start the bike and it runs fine but the top ABS light still flashes, and the tacho is not working.


As soon as you rev the bike above what seems to be about 2000rpm, things all change. The tacho starts to work but is flicking on and off in time with the ABS light. Also, the neutral light and the ignition (battery) light are flashing, at about half-brightness, and once again in time with, but alternating with, the ABS light. It's as if the tacho, neutral light and ign light are half-doing the job of the bottom ABS light. An ABS reset doesn't cure the problem.


The battery terminals are clean and in good condition. I have now removed both side fairings and the nose fairing, behind which are about 10 multi-plug connectors (plus a couple of additional small ones of 2 cables, probably horn etc). I have laboriously cleaned and greased each multi connector, and believe me when I say, after each one I excitedly restarted the bike hoping the problem would be gone, but it wasn't. Isn't. I cleaned the braided earth running up to the coil pack, but I haven't spotted any more obvious direct earths (are there any under the fuse box?). Everything inside the fuse box looks clean, but as above, I haven't removed that and started cleaning underneath yet.


I tried running a jump lead from the battery -ve and touching at any and every metal point I could find around the engine and frame, but still to no avail.


Has anyone seen this before, and is there (please!) a simple cure that I'm missing? I really enjoy riding the RT, and it's the only working (well, was-working) road bike I have, but at the moment it's heading for a one-way trip to eBay on a 99p start :sad: Ironically, I also have a similar-age car on the drive with an annoying electrical gremlin which I also can't find, so I'm rather losing the will to keep tinkering, which has always been a great hobby.


Thanks for reading my long post, all help very welcome thank you!


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Evening Cappo


That is a tough one you have there some of the things are connected & others are not directly connected.


I guess the place I would start is at the small red wire hooked to the battery (+) post.


If OK there then verify the #1 & #3 fuse is well seated & not corroded in their sockets.


From there is gets more difficult as you should run a voltage drop on the ground circuit for the dash (between brown wire at dash connection & the battery (-) post). Do this with the problem happening.


Otherwise it would help to know if the ABS works or not.


With the problem changing with higher RPM's that usually points to engine vibration related so loose connections, poor fuse connections, or grounding issues are usually at the forefront here.



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Thanks dirt rider. When you say "run a voltage drop", what do I actually need to do for that?


Re the comment about the engine vibration, it does seem to be more specific than that. If I start it, when it doesn't need any choke and thus revs are low, then slowly open the throttle, there is a very specific point at which the dash lights up. I can't tell what revs as the tacho isn't working at that time! But I suspect it's very close to 2k.

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Morning Cappo


On the voltage drop test, yes just a voltmeter (preferably a good resolution digital)


On the specific RPM that it starts working?-- That just under 2k could be the point that the alternator starts charging (but once it starts charging it should stay charging.


When it starts charging the generator light should go out. If your Gen light is not working then that could be the point that the Gen light load is taken off the dash light circuit????


Does the tac stay working once you hit that RPM point or does it quit again at lower RPM's?


You are probably going to have to verify proper power & ground at the dash circuits.


Make sure all the battery wire connections are hooked up & tight.

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Well, I have an update for you, as a result of a pointer I got from another forum. I'm ashamed to say that, having convinced myself that there was a problem with a multi-plug (after having read something on yet another website!) I piled in and stripped the fairings to hunt down the miscreant, BUT, what I did not do was check the obvious things first! Can't quite believe that but still….


So, I found Fuse 1 was blown. Replaced it and everything worked OK (except ABS needing resetting but I'm not freaked about that). All was fine until I turned the bars fully to the right, when I heard a light arcing/crackling noise behind the bars and everything popped again, including Fuse 1. So, that has narrowed it down immensely, I need to see which cables are moved when I turn the bars and then try and traced the short/chafing/break which is affected by that movement.


Much more confident now that I am on the tail of this issue and will track it down soon. Thanks again for all the assistance, I really appreciate it.

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Morning Cappo


The usual place that moving the handlebars effects is (inside) the main wire harness where it runs along the steering neck about the #1 zip tie area (probably the red or green wire broken & shorting to the brown wire)


Wires broken in that area are quite common on the old 1100/1150 bikes.


To make an effective (re long lasting) repair usually takes adding a new section of wire. Just soldering what is there now usually results a very short lived repair.

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Turned out to be the front brake light switch cable - worn through and broken just by the top of the fork leg. Sorted that out, soldered and heatshrunk, just the rest of the bike to put back together now!

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  • 4 weeks later...

Freaky coincidence - my bike Marlene developed this exact set of symptoms over the weekend and I need to sort it out. Cappo's initial description is accurate. Based on the above discussion I have eliminated any battery issues and Fuse 1 is what blows when I take a test ride. Battery shows good charge and is on trickle charger a lot - an Odyssey unit, and voltmeter reads 14.04 when the alternator runs (12.6 - 12.8 resting). I have tracked / rebuilt the front brake wires from handle to harness - no problem there. Can someone please help me organize further diagnostics so I can solve this?


Bike is 1997 R1100RT with 165,000 miles. Has been rebuilt this winter except for breaking the motor and transmission open - everything else has been reduced to individual parts for inspection / cleaning / repair / painting. Current state is rebuilt and running for shakedown testing. Still needs a throttle body synch. This electrical issue is priority one and, hopefully, the last of head scratching involved before road worthy.



- Does the foot brake switch also feed off of Fuse 1?

- Fuse 1 covers "brake light and dashboard" if I understand correctly.

- Any chart of what all the wires in the dashboard connector should be reading?

- Should I just unwrap the dashboard wire bundle back to the main harness, or further, and visually look for breaks / shorts? I have removed the front cowling/headlight and body panels for access.

- Should be a better process using voltmeter / ohmmeter to find the trouble, ideas?


At startup I get only the top ABS light flashing at 1 sec intervals, and can hear the ABS unit clicking. Bottom light not flashing so is that a sign of other ABS problem? (ABS has been fully drained and refilled. Worried about electrical aspect of ABS and NO information available that I have found yet.)


Fuse blows upon acceleration near 2K rpm so I wonder how alternator startup is related to shorting wire. My problem does not seem to be vibration as I've shaken / jiggled / pinched lots of wires trying to recreate and have not been able to yet - but that guess could be totally wrong.


Real curious about the Clymer and Haines manuals - neither is very good about electrical issues. One does not even have a fuse chart. Its like electrical system is an afterthought. Is there a chart anywhere listing dash lights and what signals refer to - especially the ABS pair of lights and sequence of flashing? Is there a good electrical resource of info for these bikes anywhere?


Thanks in advance,

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