Driver's side window works for a few days after disconnecting the battery and reconnecting. Then it fails completely. The other 3 windows always work fine. I used the re-sync procedure and it only works for a few days. It doesn't appear to be the switch in the console, because it works fine after disconnecting/reconnecting the battery (for a few days).

The drivers side mirror stops working too then the window fails. Passenger side always works. Is there a relay or computer common to both of these systems? The power seat always works fine, too.

Is there a computer or relay in the trunk I could look at or clean some contacts somewhere? Thanks in advance for the help!

 

Sounds like you have a bad door control module. You could also have something taking down the CAN or the network. Your best bet is to have someone with a diagnostic tool look to see if the CAN has faults and diagnose the problem. I have seen things like rear window motors take down the CAN and cause driver windows and seat stop working. Good Luck!

 

Thanks! I'll get a visual on the door control module, but what is the CAN and where is it? I'd like to check the wires for anything obvious before I take it to the shop.

 

Mercedes uses busses called CAN. This is a 2 wire (high and low) network. This allows Multiple control units to pass information to each other. This is why newer control units have so few wires on them. For example instrument clusters from the early 90's had 40+ wires on them The 220 S-Class had something like 9. Control units can communicate faster and vehcles are lighter due to miles of less wire. The problem is that if a control unit takes down the CAN no telling what can happen. The only way to test the CAN is with diagnostic equipment. You can check it with a multi-meter, but It would be to indepth and you would still need diagnostic equipment to see what is happening.

 

had electric windows fail on my 1994 c220, I'd try something, cleaning switches etc - it would work for a few days then stop. Turned out the winding mechanisms in the door just needed greasing - 15 years had seen them completely dry up!! Worth checking out before you go paying for electrical diagnostics and code reading shenanigans......