Hi

I have a 2002 C230 Kompressor. Recently my car would not start, so I replaced the battery. Soon after that, my car would not start again after not driving it for a couple of days. Nothing was left on. It turns out I probably have a parasitic drain on my battery.

I've been doing some research on how to locate what is draining the battery. However, I've read conflicting information on which part of the battery to connect the ammeter to. Some say the negative terminal and some say the positive terminal.

Which one is correct? Negative or positive?

My second question is: what should the "normal" current draw be on the battery for this car with no key in the ignition, doors closed, and nothing else on? Basically, when I pull the problem fuse, what should the current return to?

Thank you very much.

Paul

 

You can do either. I prefer the negative. Have all the doors, hood, and trunk latches closed. The allowable spec is less than 60 milliamps after up to about 20-30 min. Typically it is about 15-30 milliamps though. Most common items in the 203 chasis are the seat control modules (if equipped) and the overhead control panel. Make sure you do not blow the fuse in the meter.

 

i just about guarantee you that its your seat computers under your seats. We have 203 body c-class's come in all the time with a draw and its always the seat computers. they internally short out and cause a draw. i guarantee you if you put your meter on the "negative" side and wait for the car to fall asleep and then unplug the computers your draw will go down. thats typically what we see on those models.