Troubleshooting Seat Electronics W124
 

94 E420

I checked the contact switches, dissembled and cleaned them with a solution I picked up at PepBoys. They showed no sign of wear so the cleaning spray was pretty useless. There hasn't been a total failure, the headrest control failed on the drivers seat and the recliner and the headrest failed in the passengers seat. When I hit one of the switches I get a single click that eminates from elsewhere.

Would the next step be to take the seats out and take them appart to replace the motors?

No, actually the next step is to measure the resistance between various terminals in the seat switch (removed from the door) and confirm that it is in spec.

If it is, then you need to pull the 10-pin connector to the power seat controller which is under the seat, in the front. There is probably a piece of carpet with a couple of springs that is hiding it. Once the 10-pin connector is pulled, you'll need to confirm the resistances between several of the pins (to confirm the wiring isn't at fault). If that checks out, pull the four pin connector next to the 10-pin connector, and confirm that you have ~12v between the ground (brown) and the other two wires (one of the pins isn't used). If you have power there, then pull the connectors to the motors (under the seat in the back). Applying 12v to the two largest pins in each of the connectors will activate the motor. Switch polarity to get it to move back the other way.

If everything checks out there, then you need a seat controller. Not cheap.

I've just been through this entire ordeal and need a seat controller. This entire procedure is on the W124 CDROM. Sorry I don't have the resistance values handy.

Chris

I think I can let that one slide ;)

Thanks