Weird issue with seat heater display LEDs (but the heaters work!)

[sperry]

2016 F85 X5M, seat heaters seem to work just fine, however the LED indicators for the driver's seat don't work properly. The "low" LED never turns on, the "med" LED works intermittently.

I opened up the control panel, and everything looks perfect on the circuit board... I was hoping for some obviously burnt out LEDs or something I could repair, but no luck.

I purchased a used replacement control panel off eBay. Installed and tested it, and it has the same "low" LED out on the driver's seat display, but ALSO the "med" LED is out on the passenger side.

Video of issues with both panels:

Does this mean the issue is within the control panels? The documentation I've been able to find online seems to indicate that the LEDs are controlled by the logic board in the control panel, and not some feedback pins from the seats themselves... but I don't really know.

Anyone have some suggestions? I'd prefer not to keep buying and returning used control panels hoping to get one that works... the panels with the seat ventilation controls are hard to come by, and most places don't take returns.

[momoboy]

I'm not 100% sure but I believe there is a module (perhaps under the seat) that connects ultimately to the seat warmers. It would be strange to have 2 defective panels in the dash. Do you have something like Bimmerlink (or even ISTA)? I'm wondering if there is a code that might help you track down the issue.

[sperry]

I've got BimmerLink/BimmerCode, as well as a BMW-specific scan tool. I've also got an OBD2->Ethernet cable, so I could probably get ISTA working too, if I took the time.

However, I haven't noticed any codes in my scan tool that seem related, though I can't say I specifically went looking for them. If the issue were in a different module under the seat, it's weird that I'd have LEDs out on the driver's seat with one control panel, but LEDs out on *both* seats with the other control panel. But like you said, it's just as weird to have failures with two different control panels, unless this were a totally common failure... which based on the lack of other people chiming in, and a lack of similar threads on the internet, it doesn't seem like this is common.

[mrrsharma@yahoo.com]

I actually have the same issue on my driver side, I though a bulb was out or something. Following!

[momoboy]

Bimmerlink would find an issue with the panel or module. I know that only because i was recently looking for codes on Bimmerlink and it found one related to the seat heaters. Something like "button pressed for more than "x" seconds"

Is it possible ISTA might see something? Maybe?

[jeffNC]

Hey Sperry, did you ever find the cause of this LED out issue? I have the same problem on the driver's side with the "low" heated seat LED out.

[wyowolf]

I have the opposite issue... the rear lights come on but the heaters dont... the front works just fine though

[1norseman]

Originally Posted by sperry

2016 F85 X5M, seat heaters seem to work just fine, however the LED indicators for the driver's seat don't work properly. The "low" LED never turns on, the "med" LED works intermittently.

I opened up the control panel, and everything looks perfect on the circuit board... I was hoping for some obviously burnt out LEDs or something I could repair, but no luck.

I purchased a used replacement control panel off eBay. Installed and tested it, and it has the same "low" LED out on the driver's seat display, but ALSO the "med" LED is out on the passenger side.

Video of issues with both panels:

Does this mean the issue is within the control panels? The documentation I've been able to find online seems to indicate that the LEDs are controlled by the logic board in the control panel, and not some feedback pins from the seats themselves... but I don't really know.

Anyone have some suggestions? I'd prefer not to keep buying and returning used control panels hoping to get one that works... the panels with the seat ventilation controls are hard to come by, and most places don't take returns.

I have one heat seat LED that won't work when cold, but works when car is warmed up. Just started acting up this winter. When you say "intermittently" is that the same, works when car is warmed up?

In my case, the cold/warm, leads me to believe the LED or solder joint has an age related connection problem when cold and metals "shrink".
Once car is warmed up, the LED seem to works fine.

Have you tried to just heat up the solder joint with a soldering iron, if possible? I have not looked at the panel itself, so I don't know if these are surface mount LEDs or?

[sperry]

Originally Posted by momoboy

I'm not 100% sure but I believe there is a module (perhaps under the seat) that connects ultimately to the seat warmers. It would be strange to have 2 defective panels in the dash. Do you have something like Bimmerlink (or even ISTA)? I'm wondering if there is a code that might help you track down the issue.

Originally Posted by 1norseman

I have one heat seat LED that won't work when cold, but works when car is warmed up. Just started acting up this winter. When you say "intermittently" is that the same, works when car is warmed up?

In my case, the cold/warm, leads me to believe the LED or solder joint has an age related connection problem when cold and metals "shrink".
Once car is warmed up, the LED seem to works fine.

Have you tried to just heat up the solder joint with a soldering iron, if possible? I have not looked at the panel itself, so I don't know if these are surface mount LEDs or?

Yeah, I'm thinking it's most likely the soldering rather than the LED itself because LEDs don't really have intermittent failures... usually they burn out and that's that.

I haven't specifically noticed my issue related to temperature. They are basically out all the time these days. But it's been cold/cool for a while. Maybe when it's 100F out, the middle one will start working every now and then. lol

The LEDs are surface mount (or I would have replaced them already). I recently got the equipment to do SMD LEDs, so once I have the time, my plan is to replace them all. I've also lost the right turn signal LED in the dash, so I need to replace that too (probably left and right turn signals, just to be sure they match). I might just try using the hot-air wand to just re-seat the existing LEDs... there's not really any harm in trying that, I suspect. Maybe that's the easiest way to fix this, if it indeed is a cold solder joint.

I just need to find the time to do it, but I will post up here the results once I get around to it.