The two modules are not the same part number. You can either unplug it when you are not using it, add a relay to switch power from another line, or buckle down and replace the module.

 

Looks like Mercedes got another person with their electrical problems. Same thing happened about two months after I bought my C240. Apparently it's a pretty common problem among Mercedes C230/C240 If the parts aren't the same part number I will suggest not getting them. Their numbers are different for a reason. If it's not to much of a hassel just like the other person said, unplug it when not in use. I personally wouldn't worry about replacing is as I'm sure it's expensive, especially if you buy it from Mercedes directly. You could do what I actually did. I installed a automatic kill switch to the battery, so when I turn the car off I flip a switch and cut all power to the car. Also makes it pretty much theft proof unless somebody manages to find out what you done. Only problem with that is you won't be able to lock the car, but I never kept anything in my car I was worried about getting stolen, so it didn't both me in the least bit. It's the cheapest option you have besides just disconnecting the module every time you get out of the car, which will get very annoying very quickly if you're one to move you seat a lot.

 

Yes, the part is expensive, and you have no guarantee that the new module won't have the exact same problem... Makes me glad that I don't have the power seats. By the way, zombe was talking about a battery kill switch. That's one possible solution, but you could set it up different, and still be able to lock the car. Most people place the kill switch right at the battery terminal. Instead you can route the battery wiring, and place a kill switch right under one of the under body panels. Set it up to where you just have to remove one bolt, pull the panel down some, and engage the battery. Still think it would just be easier to unplug the module when not in use though...

 

Or add a relay that puts it on ignition-switched power. There's a convenient line to the cigar lighter that you could route to a relay. Put a standard little Bosch unit inline with the seat controller and you'll have automatic connect-disconnect. If you're not comfortable with that any auto electric shop should be able to do it. A new module should fix the problem if there are no other faults.

 

Thanks for the reply.

It seems to me adding a switch to kill the power coming out of the battery prevents any future drain but create a problem of not being able to lock the car. I imagine the clock or maybe other things may get reset as well.

I am thinking about adding just a switch in front of the 12V/Gnd cables before the connector. Yes, it is not tie to ignition (via a relay) but maybe easier to flip that switch instead of trying to plug in the connector into the seat control unit or wiring the ignition wire to the circuit. Do you happen to know how much is the DC current draw when the power seat are moving?

There is a small plug next to the SCM underneath the seat but not on the SCM itself. I wonder if that is a CAN bus connection for the SCM. It has three wires which is consistent with CAN. I read on another thread that the reason battery is draining is becasue CAN not go to sleep. I may try to unplug that and leave the power cable in and see if the situation improves. Any thoughts?

 

I have the same problem with my 01 240. I found this tread on fixing the problem by turning off the power to the seat while the car is not running. I probably will try it this weekend. Hope it helps .

http://www.benzworld.org/forums/w203-c-class/1403233-diy-how-fix-your-power-seat.html

 

I had the same problem this January with my C230K 2002, passenger seat pulling >500mA, my new battery would not last a weekend. Since I didn't want to mess up with the winter and didn't want to disconnect the power seat, I got this taken care of at the dealership for about $700. I did ask to check the drain/load after the new parts were replaced. It's been two months, problem is gone, peace of mind was worth $700... or lose seat adjustment.

 

Electric Seat Adjustment

The electric seat adjustment (tilt) on my 2004 Mercedes C230 Kompressor has stopped working. I have checked the clear fuses in the engine compartment and they are all OK. Please help. Thanks.

 

The electric seat adjustment (tilt) on my 2004 Mercedes C230 Kompressor has stopped working. I have checked the clear fuses in the engine compartment and they are all OK. Please help. Thanks.

Thanks again Rodney.
Turned out it was Fuse #2 , 30 Amp, in the trunk that did the trick.
Cheers - Vipin.

 

Check fuses 27, 29 and 34 on the cabin panel (located on the end of the dash, driver's side.) Here's a full list of fuses and relays:

Benzbits: W203 Fuses

 

Thank you very much. Will try tonight and let you know.
Have a great day.