Driver's side heated seats not working
 

Hello, the driver's side heated seats stopped working. When I push the button it just flashes and turns off. The passenger side works fine. If anybody can give me any suggestions on how to troubleshoot (at which wires to check the resistance?) and possibly a PDF for removing the seat if that's what is needed. Thank you in advance.

Most likely a short in the heating wire circuit. I know there's info on this forum about pinouts and such on the connectors because I used that info a while ago. Search around for it - I'm sure it can be found.

As far as removing the seat... no PDF needed... remove the securing bolts and disconnect the wire plugs.

Fuse? Relay?

My first guess would be broken wiring in the heating unit itself. Lots and lots of flexing over the years.

Really though, how often do you really move the chair around? lol Wires would be my last thing I'd check.

Everytime you sit on it! :)

You physically move the chair everytime you get in?

The heating coil/pad is right below the surface of the seat... that would get stressed every time we wiggle and jiggle ;)

yes, because my wife and I have different settings so we move the chair when the other drives. That being said, the heating stopped working when I was testing the limits of the chair movement.

I understand your logic, but I've had vehicles with heated seats since the mid 80s, never had an issue with the wires on the heating elements, ever. Could be the pressure sensor in the seat, had that issue on an old Audi

I definitely appreciate the input. I haven't had time to work on it this past week, but will hopefully get to it this weekend. If/when I find something, I'll update the thread.

I'd start by having a meter on the plug that goes to the heater element, see what kind of volts you get when you hit the button.

I've had 3 cars with heated seats since 2002... and still have all 3! So, granted, it's not a huge number of cars. BUT... the heating on the passenger seat on the MB stopped working a couple years ago and ohming the heating connector showed a break in the heating circuit somewhere (no continuity). When I talked to the place I got it from (they sell a lot of used German cars), they said it wasn't too uncommon to get a break in one of the wires of the heating circuit. I haven't gone any further with this so that's about the extent that I can talk about it :)

Oh... the light on the dash button would blink a few times when pushed and then turn off.

Troubleshooting heated seats
 

https://cimg9.ibsrv.net/gimg/www.mbw...d107941558.jpg
This is the driver's seat module
https://cimg8.ibsrv.net/gimg/www.mbw...74cd060c19.jpg
The 2 copper pins in the middle are in the seat where where the from line from the switch attaches

This is what I tried today on both the driver's and passenger seats, (the passenger works fine, the driver's side the heating light blinks and turns off.
1. I disconnected the heating cord going to the seat, the passenger side had the same symptoms.
2. I checked the resistance on the heating wires going to the seat, ~2 ohms.
3. I checked the voltage on the wires coming from the switch, it would jump momentarily to ~11 volts while the switch stayed on.
4. Lastly, I put the passenger seat on the driver side and the symptom still persisted (turn on for a second and shut off)
My buddy thinks it might be the seat module (pictured) but I don't think so because the passenger which works and has a good module still didn't work on the driver's side.
any suggestions?