Heated Seats, not working

January 3

It seems that the heated seats on my bike aren't working. I'm not sure if they were working when I bought the bike (hindsight, I should have checked ) so I don't have a point in time they might have stopped working. Dash lights come on to show they are turned on, both front through the menu and back with the switch, but neither seat heats up. The grips work just fine. I bought a Corbin seat and wired with the BMW plugs and it doesn't work either, so something with the bike and not the seats seems to be the direction things are pointing. I checked the voltage in the plug for the front and it shows 8.3 volts with the heat turned off in the menu and 10.3 volts with the heat turned on, regardless of setting. Both seem odd to me but it was a "I wonder what the voltage is" check, not one knowing exactly what to check for.

Any input on where/how do start tracing down what might be the problem? I'm not sure if the digital version of the service manual has wiring diagrams or pin-outs, or if those would even help me. I hate messing with wiring so I am hoping it is something a little more simple than that.

January 3

If you are using an aftermarket seat, the heating unit may not have the same current demand as the OEM heated seats and the CANbus might shut that circuit off if it is out of the expected range. I have Sargent rider & passage seats on my ‘15 RT and on occasion the CANbus has turned the circuit off when the temp set was up toward maximum. It hasn’t cut out enough times for me to dig into the issue, but I suspect there is a unexpected over current draw that shuts that circuit down.

January 3

4 hours ago, Stresspuppy said:

It seems that the heated seats on my bike aren't working. I'm not sure if they were working when I bought the bike (hindsight, I should have checked ) so I don't have a point in time they might have stopped working. Dash lights come on to show they are turned on, both front through the menu and back with the switch, but neither seat heats up. The grips work just fine. I bought a Corbin seat and wired with the BMW plugs and it doesn't work either, so something with the bike and not the seats seems to be the direction things are pointing. I checked the voltage in the plug for the front and it shows 8.3 volts with the heat turned off in the menu and 10.3 volts with the heat turned on, regardless of setting. Both seem odd to me but it was a "I wonder what the voltage is" check, not one knowing exactly what to check for.

Any input on where/how do start tracing down what might be the problem? I'm not sure if the digital version of the service manual has wiring diagrams or pin-outs, or if those would even help me. I hate messing with wiring so I am hoping it is something a little more simple than that.

Afternoon Stresspuppy

Try riding it with the seat heater on, they can sometimes fool you a bit if you are just trying the seat heat sitting still at engine idle.

I have been on 1200RT wetheads that will fry your rear & others that hardly get warm. Not sure if that is due to a computer firmware iteration or a malfunction.

In any case you aren't the only one, you might want to read this thread__

https://www.bmwsporttouring.com/topic/87487-2017-rt-heated-seat-not-working/

You might also want to drop by your BMW dealer & talk to them as they might have a service advisory on it as there have been some complaints on seat heat.

January 3

Check your pins on the connector. Right after I bought mine I sent it to Russell for a new seat with heat. Plugged it it… no bueno. After days of troubleshooting I found one of the male pins had fallen out of that goofy connecter. I changed the connector and it worked.

Since you have same issue on both seats, not likely same as my issue.

DR is right, these aren’t instant heat. It takes a while.

January 3

1 hour ago, dirtrider said:

Afternoon Stresspuppy

Try riding it with the seat heater on, they can sometimes fool you a bit if you are just trying the seat heat sitting still at engine idle.

I have been on 1200RT wetheads that will fry your rear & others that hardly get warm. Not sure if that is due to a computer firmware iteration or a malfunction.

In any case you aren't the only one, you might want to read this thread__

https://www.bmwsporttouring.com/topic/87487-2017-rt-heated-seat-not-working/

You might also want to drop by your BMW dealer & talk to them as they might have a service advisory on it as there have been some complaints on seat heat.

Thanks dirtrider. The last time I rode I had it own and didn't feel anything with the stock seat. I had on a couple of layers but I would think I still should have felt something. So I have a few rides as well as running at idle with no luck.

Thanks for the thread. Good info. Summary seems to be '14-'16 models would burn your butt while '17-'18 tended to have issues with heating (only a little or not at all). Several took theirs to a dealer with limited success. Unfortunately the dealer is about an hour away so I'll have to plan a trip with a follower to get me back home. Sounds like there isn't much I can do on my own to chase it down if the dealers didn't have a quick/easy fix. I'm going to call the service department just to see, but sounds like a trip there may be needed.

25 minutes ago, Skywagon said:

Check your pins on the connector. Right after I bought mine I sent it to Russell for a new seat with heat. Plugged it it… no bueno. After days of troubleshooting I found one of the male ins had fallen out of that goofy connecter. I changed the connector and it worked.

Since you have same issue on both seats, not likely same as my issue.

DR is right, these aren’t instant heat. It takes a while.

Good idea on the pins. I've had those connectors apart several times so all things are possible in terms of bending one. That would sure be an easier fix than going to a stealer.

January 3

As I recall, the RT shuts off the seat heat when idling for a time. Have you checked it at speed?

January 4

Well that would do it. I took a ride on Monday and it was miserable. I was so bundled up I don’t know if I would have noticed if it did work. I’ll find a day when it isn’t so icky and go for a short ride and see what happens. The grips work while it is sitting and idling so I wonder if they would be different from the seats?

I spoke to the dealer and he said they could get me in just about anytime to check it (he said no one wants to ride in Jan and Feb - sissies! 🤪 so they are usually pretty open). I may ride up there in the next week or so after I give your suggestion a try.

January 4

12 hours ago, Stresspuppy said:

The grips work while it is sitting and idling so I wonder if they would be different from the seats?

Morning Stresspuppy

If it shuts the seats off at idle (this is an IF not a definite) then it would not be due to strictly engine idle. It would be more due to a low charging state (low stator output at curb idle).

The wethead (water cooled) boxer has an internal alternator that has a lower idle output & lower max output than the older hexhead/camhead bikes. With headlight ON, heated grips ON, fuel pump ON, other accessories ON, etc it might have the ability to shut down high draw things like heated seat & heated grips if it sees system voltage dropping below a low-trigger threshold.

I have no idea on if BMW would program this in (or even IF they have it programed in) but if I was programming it then the heated seat(s) would be the first thing that I would shut down at low system voltage, then if still not enough system voltage to keep the system happy the heated grips would be shut off next.

In any case, that is why I suggested in my first post above that you "Try riding it with the seat heater on".

I can't find anything from BMW about shutting the seat heat off at idle, or at high system demand at curb idle but it wouldn't surprise me if they worked that into the later wethead programming.

If you ride it for a quick test, or just for a short time, then try riding it with heated grips off & keeping the engine RPM's a bit higher (not a lot of engine idling sitting still). If you have heated gear then turn that down or off for the ride test (especially at idle).

You need to first determine IF the heated seats are even working, if you determine that then next you can try to figure out if they do shutdown at high system demand at curb idle.

If you take it to the dealer then be sure to tell them that you ride with the heated grips ON & any heated gear you use ON so they can duplicate that system load while checking the seat heating out.

January 4

For what it’s worth, I have ridden 2 different Wethead RTs over a combined 175000 miles and have never had the seat heat spontaneously turn off. I always have grip heat and heated jacket on if the seat heat is on. Don’t think your issue is a lack of system capacity, providing the charging system and battery are up to snuff. Good luck!

January 4

Good morning dirtrider. Fantastic info, thanks. I hadn't thought about it being "smart" enough to start shutting things off like that. Highs are in the low 40s here at the moment so not the most fun ride but also good testing weather. It's supposed to rain on Saturday but if things are dried up and clear, I will try to take a test ride Sunday morning and keep all the things you mention in mind.

My limited gear (socks, gloves) are battery operated for now. Ultimately, if I continue to ride in the cold, I'll research good gear that hooks into the bike and then setup necessary connections for that. I didn't want to go that far if I "whimp out" and don't ride in the cold (below 45 is my threshold).

I'm wondering if it is worth doing a load test on the battery just to eliminate that. I haven't had issues with anything else and it starts right up so probably not a problem. I have a load tester, so easy to do. Can this be done with the battery in the bike or should I disconnect everything and pull it out? I'll also hook it up to my CTEK charger/maintainer just to make sure it is topped off. I highly doubt it's battery related, but you just never know. Better to eliminate things.

January 4

19 minutes ago, Stresspuppy said:

Good morning dirtrider. Fantastic info, thanks. I hadn't thought about it being "smart" enough to start shutting things off like that. Highs are in the low 40s here at the moment so not the most fun ride but also good testing weather. It's supposed to rain on Saturday but if things are dried up and clear, I will try to take a test ride Sunday morning and keep all the things you mention in mind.

My limited gear (socks, gloves) are battery operated for now. Ultimately, if I continue to ride in the cold, I'll research good gear that hooks into the bike and then setup necessary connections for that. I didn't want to go that far if I "whimp out" and don't ride in the cold (below 45 is my threshold).

I'm wondering if it is worth doing a load test on the battery just to eliminate that. I haven't had issues with anything else and it starts right up so probably not a problem. I have a load tester, so easy to do. Can this be done with the battery in the bike or should I disconnect everything and pull it out? I'll also hook it up to my CTEK charger/maintainer just to make sure it is topped off. I highly doubt it's battery related, but you just never know. Better to eliminate things.

Morning Stresspuppy

As long as it starts up OK on a cold morning then you have enough battery. If (big IF here) it does shut high draw accessories off at curb idle then that would probably be more system voltage (alternator output) related than battery related).

If you want to test something then monitor battery voltage and/or system voltage with the engine idling & your heated grips & heated seats on.

If you are looking at system voltage then you would probably see a system voltage drop when you turn your heated seats on at engine idle. It might not show as easily if just monitoring battery voltage.

I'm not sure on the wethead up boxer bikes (never looked into it) but there is a good chance the heated seats are pulse-width modulated so could be difficult to test (open circuit) voltage at the disconnected seat pigtails. If you have an older analog meter (swinging needle) then use that on the seat pigtail terminals with the seat load (or a resistor load) on the circuit.

The thing is, with heated seats, even if they shut down at curb idle & low system voltage the rider probably wouldn't be able to feel it for while due to sitting on (insulating) the already warm seat, unless a very long idle time or the bike wasn't ridden at speed long enough to properly heat the seat.

As I mentioned above, I'm not even sure if they do shut the seat heat off at low system voltage but the wethead alternator output is not that great at low engine RPM's so it's possible BMW slipped that into a later system firmware update. If a person does their own service then that bike would never get a firmware update, if the motorcycle is dealer serviced (and connected to the dealer computer) then it would probably automatically get any firmware updates.

January 4

36 minutes ago, dirtrider said:

Morning  Stresspuppy

As long as it starts up OK on a cold morning then you have enough battery. If (big IF here) it does shut high draw accessories off at curb idle then that would probably be more system voltage (alternator output) related than battery related).

If you want to test something then monitor battery voltage and/or system voltage with the engine idling & your heated grips & heated seats on.

If you are looking at system voltage then you would probably see a system voltage drop when you turn your heated seats on at engine idle. It might not show as easily if just monitoring battery voltage.

I'm not sure on the wethead up boxer bikes (never looked into it) but there is a good chance the heated seats are pulse-width modulated so could be difficult to test (open circuit) voltage at the disconnected seat pigtails. If you have an older analog meter (swinging needle) then use that on the seat pigtail terminals with the seat load (or a resistor load) on the circuit.

The thing is, with heated seats, even if they shut down at curb idle & low system voltage the rider probably wouldn't be able to feel it for while due to sitting on (insulating) the already warm seat, unless a very long idle time or the bike wasn't ridden at speed long enough to properly heat the seat.

As I mentioned above, I'm not even sure if they do shut the seat heat off at low system voltage but the wethead alternator output is not that great at low engine RPM's so it's possible BMW slipped that into a later system firmware update. If a person does their own service then that bike would never get a firmware update, if the motorcycle is dealer serviced (and connected to the dealer computer) then it would probably automatically get any firmware updates.

Tħere is part of me that wants to tinker and figure this out, but another part of me says it doesn't want to deal with the hassle. For the big IF, I'm not sure I care as much if it is turning off, I am trying to figure out if it ever turns on. If it is warm, I've got my gear on, like you mentioned, it would take a while. But I don't think it turns on.

For "fun", I'll check the battery voltage at idle then see if there is a drop when turning on the grips since I know those work. If so, I'll try the seats.

I used a digital multi-meter with tiny probes to get inside the plug. It showed 8 volts with the seat off and 10 with it on (regardless of temperature level setting). Neither number made sense to me based on the logic in my head. I would expect 0 volts if it is off and then an increasing voltage as the temperature goes up. But this is speculation from a shade-tree electrical person. I can turn a wrench, but electrical is not my forte.

Good point on the firmware updates. Coming from a very simple bike with no such thing, I forget there is something with software controlling things and can be updated. When I take it to the dealer, I'll ask them to confirm it has the most recent just to be sure.

January 4

20 minutes ago, Stresspuppy said:

I used a digital multi-meter with tiny probes to get inside the plug. It showed 8 volts with the seat off and 10 with it on (regardless of temperature level setting). Neither number made sense to me based on the logic in my head. I would expect 0 volts if it is off and then an increasing voltage as the temperature goes up. But this is speculation from a shade-tree electrical person. I can turn a wrench, but electrical is not my forte.

Morning Stresspuppy

If you put a digital volt meter on the pulse-width modulated brake light/tail light circuit on a BMW motorcycle (one wire lights same bulb as tail light & also as the brake light)

You will see the running voltage is pulsed to average out at about 8 volts DC. When the brake is used that same wire will instantly rise to a little over 12v DC. If you put an analog meter on that same circuit you can usually see the actual pulses in the needle dips or swings.

Again, I'm not sure on the seat heating circuit but pulse-width circuit control would make more sense as that uses less power for all except high (unless high is also pulse-width modulated).

If the seat was an older generation conventional resistor system for lower settings then that resistor heat would have to be handled in either conventional resistors or longer resistor wire) but either way it would still use about as much power as the seat on high & would probably be limited to only low & high. Or have a couple of heating elements in the seat itself with independent input to each.

With a pulse-width system the system actually cuts the current between pulses so that it is basically an open circuit on the off-cycle so isn't using any power on the off part of the cycle. (A great power saver if seat is operated on lower settings). Pulse-width operation can also give a number of different heat settings using just one electronic controller & one wire plus a "low" to the component.

January 4

Well, with a GS-911WiFi you can check and see if the unit turns on. Or if the computer acknowledges to turn on seat heating.

I was told by a service advisor once that the seat heat on the newer RT’s didn’t work, unless the ambient temperature was below a certain value. So maybe a update or reboot could solve the problem.

Also please note that the cable for the seat heat is only a short cable, with a second connection a little further inside the bike. Maybe it has been unplugged there or pulled loose by previous owner.

As for high power consumption, the bike will alert you if you use more current than the alternator can supply. In that case the voltage of the battery will start to drop. When it gets to a certain value, I think in the low 11’s VDC or lower, you will get a alert on your dashboard.

I experienced this several times with my 2018 RT, when I would use heated grips, heated seat, heated jacket & gloves and use high beam, combined with my Clearwater LED lights on full output.

January 4

15 minutes ago, Bernie said:

Well, with a GS-911WiFi you can check and see if the unit turns on. Or if the computer acknowledges to turn on seat heating.

I was told by a service advisor once that the seat heat on the newer RT’s didn’t work, unless the ambient temperature was below a certain value. So maybe a update or reboot could solve the problem.

Also please note that the cable for the seat heat is only a short cable, with a second connection a little further inside the bike. Maybe it has been unplugged there or pulled loose by previous owner.

As for high power consumption, the bike will alert you if you use more current than the alternator can supply. In that case the voltage of the battery will start to drop. When it gets to a certain value, I think in the low 11’s VDC or lower, you will get a alert on your dashboard.

I experienced this several times with my 2018 RT, when I would use heated grips, heated seat, heated jacket & gloves and use high beam, combined with my Clearwater LED lights on full output.

Morning Bernie

I haven't put a GS-911 on the wethead looking for seat heating issues & don't have one handy at the moment to play with.

Does the GS-911 just show COMMANDED seat heat ON (same as dash showing seat heat ON but no actual seat heating due to issue) or will it also show actual seat heating voltage, or something to verify actual seat heating (not just commanded?)

It's kind of a 2 part system, one side is the command side & the other side is the reaction side, or power out TO the seat side.

I presume that you didn't (or couldn't) notice if the system turned the seat heat off sometime prior to dash warning coming on? If the seat was still actually heating (not just residual heat) right up to dash warning then that could tell us something about if it automatically shuts off or not at low system voltage.

January 4

I think the GS911 will only show if the function for set heat or grip heat is selected or not.

I don’t think it has any other diagnostic criteria.

Yes, your display should also show if the feature has been activated.

I know when I reported the seat heating problem to my dealer back in 2018, he told me that there is nothing wrong. I continued trying to use the seat heat and eventually it started to provide heat. I don’t know if it is a “burning in” process or if it is a “learning process”. But it didn’t make any sense back then either.

If the system did turn off the seat or grip heating to preserve battery capacity, it didn’t set any alerts or warning ⚠️ until I received a red Triangle warning about low voltage on the battery.

January 4

18 minutes ago, Bernie said:

...

I know when I reported the seat heating problem to my dealer back in 2018, he told me that there is nothing wrong. I continued trying to use the seat heat and eventually it started to provide heat. I don’t know if it is a “burning in” process or if it is a “learning process”. But it didn’t make any sense back then either.

If the system did turn off the seat or grip heating to preserve battery capacity, it didn’t set any alerts or warning ⚠️ until I received a red Triangle warning about low voltage on the battery.

Thanks Bernie. My bike had 54k by the previous owner when I bought it so I would hope if there is a "burning in" in period it would have been done long ago. But you never know. I'm planning a trip to the closest dealer (about an hour away) and based on what I am hearing/reading, my guess is I will get similar responses on either there is nothing wrong or nothing they can do. I hope not as I wouldn't be against a little bit warmer tushy at times but not at the expense of lots of time at the dealer and lots of $$$. If nothing else, it seems I am not the only person that has had this problem or something similar with the seat heating so I'm not going completely crazy. Yet.

January 4

Well, maybe the previous owner never used the heated seat Ann maybe even had a aftermarket seat without heat?????

Good luck with your dealer, most likely they are a much better dealership. I don’t think BMW can afford to have too many crappy dealers, like my local *****DP.

January 4

Now that I think about, when I came across the service records from the original owner (it's a 1 owner, now 2, bike) it lived the vast majority of its life in FL. I can't imagine heated seats were thought of much there - but you would obviously know better than I do

January 5

I hate the heated seat. It makes me feel like I crapped my pants, so I keep it off at all times. Same with the car. Yes, I ride where it's cold, but my butt isn't exposed at all. Heated jacket is a much better choice for me.

January 5

I liked the heated seat when riding thru the Alps on a rented RT (had never had one before). Wouldn't mind having one on my bikes now. And I do love my heated jacket, and grips on one of the bikes.

January 5

Interesting topic, I love electrical troubleshooting. I don't see where you checked the seat resistance or continuity.

January 5

3 hours ago, NewportCycle said:

Interesting topic, I love electrical troubleshooting. I don't see where you checked the seat resistance or continuity.

Morning NewportCycle

Not a bad idea but probably not likely the problem as neither (separate) heating element work in the stock seat & the aftermarket replacement seat doesn't work either. Possible but the chances of all of those heating elements being open is pretty slim.

January 5

Morning Bernie, Stresspuppy

I found this in the 1200RT wethead riders manual.

It says seat heat "might have been temporarily switched off" but doesn't say if it switches off right at low voltage warning icon triggering, or shortly before low voltage warning icon triggering.

I did call a fellow rider that I occasionally ride with (the one with the 1200 wethead that doesn't get very hot) & he told me that it can take up to 20 minutes or so to start feeling heat on the riders seat (he doesn't ride with a passenger so can't say if that seat is the same).

He also said it works better (gets hotter) now that the seat is has a lot more sitting time on it but still not as good as his old 1200 hexhead was.

I also asked him if the seat heat was ambient temperature dependent? He told me he didn't think so but he can't remember ever using it when it wasn't cold enough to actually need the seat heating. I didn't see anything in the riders manual about the seat being ambient temperature sensitive. To me having the seat being ambient temperature sensitive would eliminate one of the main reasons that I use mine & that is to quickly dry the seat off after a heavy dew night (I usually wipe the moisture off then turn the seat heat on to quickly dry it). I also use it on my 1200 GS to dry the seat quicker after a deep stream crossing at speed or when riding in heavy rain.

He did say the engine needs to be running for the seat heat to work but we all already pretty well knew that.

A quick search online shows there are number of 1200 wethead seat heating complaints.

With all those complaints my guess is there is probably some sort of BMW service bulletin or service advisory on the wethead seat "heating issue", either explaining the operation to the customer, or actually addressing the root of the issue.

Stresspuppy, with the heated seat being computer controlled (and circuit computer protected) make sure that you do a complete key-OFF for at least 1 minute after unplugging the seat, or after changing the seat with the engine running as that will do a seat-heating circuit re-set.

January 5

I do remember that BMW changed the seats with the 2018 models. They looked the same as the earlier models, except they had a RT logo on them. I don’t know if this means they changed foam density or used smaller heating coils.

I also know the seat on my 23 RT feels more comfortable to me. But I have only used the seat heat once and didn’t pay too much attention to it, except I remember it being 35F and I was comfortable.

January 5

Know anyone close that you can swap the seat to see if your seat is defective?

January 5

11 hours ago, Rainman48 said:

I hate the heated seat. It makes me feel like I crapped my pants, so I keep it off at all times. Same with the car. Yes, I ride where it's cold, but my butt isn't exposed at all. Heated jacket is a much better choice for me.

Rainman48 - I'm just trying to figure it out so I can have the option to use or not use. Right now, I don't seem to have that choice. But I get your point, not all butts need/want heat.

1 hour ago, dirtrider said:

Not a bad idea but probably not likely the problem as neither (separate) heating element work in the stock seat & the aftermarket replacement seat doesn't work either. Possible but the chances of all of those heating elements being open is pretty slim.

dirtrider - I would agree. If neither is working, if feels more like it is some controller or something upstream from the seats. I'm willing to give it a go if someone provides some guidance on how to test for that.

1 minute ago, Wayne Johnson said:

Know anyone close that you can swap the seat to see if your seat is defective?

Wayne Johnson - Unfortunately, no. I'm going to reach out to some local riding groups (not brand specific) and look again for a BMW riding group in the area. You'd think living in the capital city (Richmond VA) there'd be something but this seems to be a bit of a dead zone for stuff (I tried to find some rider training courses just to up my skills and the only things I could find, if they were even having them, was either in Northern VA or down in the Virginia Beach/Newport News area - there is a military base down there).

January 5

2 hours ago, Stresspuppy said:

dirtrider - I would agree. If neither is working, if feels more like it is some controller or something upstream from the seats. I'm willing to give it a go if someone provides some guidance on how to test for that.

Morning Stresspuppy

I don't have anything (resistance wise) for testing the actual seat grid for resistance, or even a partial open. I'm pretty sure that it is a carbon type grid so you could have a number of (broken) open fibers so could still see some sort continuity but who knows if it is the correct resistance or way out of line.

On testing the controller side. You do have a dash indication so the control side (input side) is telling the module to turn the seat heat on.

So you would probably need to look at the controllers output side. With a 5 position heat setting that almost assures it is a pulse-width type current output to the seat. To test that you will probably need to make a short break-out harness to go between the seat & the pigtail harness. Then with the seat plugged in & engine running you need to measure the voltage taken at that break-out harness.

Here is the problem, you don't really know how your digital voltmeter will average the pulses so that would have to be determined.

January 5

dirtrider,

I do have an analog meter, I've just gotten used to my digital that I never use the analog. Seems like it was a good idea to at least keep it around. For the breakout harness, I assume I would need male and female connectors to patch in between the bike harness and the seat. I have connectors that are the same as what is on the seat but I don't have the ones like on the bike harness. Is there a different way to do this? I'm guessing the bike is smart enough to shut it off if it doesn't sense the resistance (or something) of a seat being there.

Whether this uncovers something or not, learning new stuff is a good thing, and fun!

January 5

I may have a spare bike side connector. I'll check today when it stops raining. Shoot me a picture of yours and if it matches and you need it, I can mail it to you.

January 5

1 hour ago, Stresspuppy said:

dirtrider,

I do have an analog meter, I've just gotten used to my digital that I never use the analog. Seems like it was a good idea to at least keep it around. For the breakout harness, I assume I would need male and female connectors to patch in between the bike harness and the seat. I have connectors that are the same as what is on the seat but I don't have the ones like on the bike harness. Is there a different way to do this? I'm guessing the bike is smart enough to shut it off if it doesn't sense the resistance (or something) of a seat being there.

Whether this uncovers something or not, learning new stuff is a good thing, and fun!

Morning Stresspuppy

For terminals just use what you have or can find, for female pins you can squeeze down slightly larger terminals with pliers, or use very small alligator clips, or even use a tight fitting small diameter hose to hold the wire in contact with the mating terminal (put a lump of solder on the wire to allow it to have better contact.

For the male terminals either cut down a larger one, or open up a paper clip then pound one end flat with a hammer (then file to fit) then solder your break-out wire to that, then cover all but the very end with tape or heat shrink. Or, just add solder to the wire end directly then pound it flat with a hammer (I have done this many times to make a quick connection to an oddball female terminal.

For sure the controller will shut the circuit down if something in the power side is shorted hi to low, or if hi is shorted to ground. Or even if the resistance in the power side is too low (high power draw).

If the power side circuit is open, I'm not sure if it will shut the circuit down but a GS-911 usually gives an open circuit indication with a related fault code. Probably no reason to shut it down and/or trip a dash warning for high resistance or an open as it isn't a safety related circuit like headlight or tail light.

January 5

I’m not home to reference my manual, but are the heated seat circuits physically fused vs electronic?

January 5

14 minutes ago, Limecreek said:

I’m not home to reference my manual, but are the heated seat circuits physically fused vs electronic?

Afternoon Limecreek

It's electronically fused something close to a crowbar type circuit protection.

January 5

1 hour ago, dirtrider said:

Afternoon Limecreek

It's electronically fused something close to a crowbar type circuit protection.

Thanks DR - assumed as much, but you never know.

January 5

I think I'd try to rig up a pigtail and plug seat directly into 12v power source, verify the seat's are good.

I'm perplexed, the 8.3v with the switch off, was this test measured to a frame ground or to the negative lead on the socket? Having power available to a constant current circuit makes little sense is the circuit computer ground switched?

January 5

1 hour ago, NewportCycle said:

I think I'd try to rig up a pigtail and plug seat directly into 12v power source, verify the seat's are good.

I'm perplexed, the 8.3v with the switch off, was this test measured to a frame ground or to the negative lead on the socket? Having power available to a constant current circuit makes little sense is the circuit computer ground switched?

Evening NewportCycle

The switch side (control side) seems to be working as the dash indication indicates heating selections. That dash indication doesn't come on if the control side is not working.

It's the power-out side that seems to be the problem (or if it even has a problem).

I seriously doubt BMW would run a constant-current to a 5 position heated seat, way too many resistors & switching controls.

It is most likely a pulse-width type modulated system with the module controlling the pulse-width of the on-off-on-off-etc cycles. The longer the (on) pulse & the shorter the (off) pulse then the hotter the seat gets. Simple, fewer components, definitely lower power consumption on all but high. The easiest way to get 5 position seat heating selection with a simple low amp input control.

I'm not sure that I would plug the seat into direct 12v until I understood if the high runs at a 100% pulse (on). If it only uses a 75% or 80% (on) pulse for high then 12v could burn out the carbon fiber grid. If high is designed to run at a 100% (on) pulse then it could be tested at a full 12v but we don't know the circuit design for high (at least I don't).

That 8.3 volts could be a highly resisted (very low current) verification current, that way the system can sense open circuit for an "open circuit fault". It probably needs to be measured again with the seat load on the circuit (therefore the break-out harness mentioned above). My guess is that 8.3v will be gone with the seat load on the circuit.

January 6

Thanks.

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Heated Seats, not working

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