Mercedes-Benz Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
So I left my dome light on and my battery drained- obviously. Jumped it and let it run for 20 minutes and drove it around. Battery was dead the next morning. Jumped it ran for 30+ and drove it for 30 minutes. Battery was dead. So I bought a new battery. Next morning battery was dead. Yeah, I turned off the dome light the first time. So I take it into a local auto electrical shop- no MB dealer within an hour- anyways after three hours they say it's a drain from the phone and nav system. They said they removed the fuses but the car won't run without them. Now I've paid 150 and they tell me to goto the dealership.

Any one had the same problem or advice?
 

·
Registered
Joined
·
5,368 Posts
Welcome to the forum.

The 2001 C320 is notorious for their defective power seat modules. Don't worry, nothing money can't fix, they are not cheap. It's funny that they would say the nav system because it does have a constant draw with the ignition off but it's so small that I doubt it would kill a battery, so for now, pull the connectors off the seat control modules under both seats (set the seat to where you want it first, obvisouly) and get a battery charger and charge the car, don't drive it with a dead battery, puts a strain on the charging system and 30 minutes is not enough anyway. $150 was well spend on bad advice, that's what most mechanics do, he's probably never seen a 2001 C320 before and doesn't know how bad the electricals are on MBs. You maybe able to get the modules from a salvage yard, just don't get them from a 2001/2002. Also there are some discount MB places like Duval where you can save a buck.
 

·
Registered
Joined
·
46 Posts
I have been thinking about this problem and I remember reading a thread on the wbworld web site where a member had a problem and everyone chimed in and said it was his seat modules. Turn out in his case it was not. It was his cooling fan not shutting off. This fan was tied into his NAV AND RADIO FUSE.

I have pasted his thread here:

Ok follow up, and found the culprit, 1st of all let me state, if you remove the negative battery terminal you will ONLY find a ground short!!!!!!!!!!! you will NOT find a short with a particular electrical item- seats, lights whatever, that is because those items most have a + and - to actually be working or in this case DRAINING YOUR BATTERY. Now for the update, after using my mulitmeter with the NEG battery terminal or wire off I found NOTHING the amps stayed continuous, however when I reattached the NEG battery wire, I noticed a -1 amp loss every 3-4mins, with my seats unplugged no less the whole time, so I went to the fuse schematic and looked for the Command SE unit, that would be fuse #64 found on the drivers side fuse box under the hood, pulled that fuse............the meter stayed at 5.5amps no more problems, plugged the seats back in one at a time and kept an eye on the meter at 5 min intervals..........NO PROBLEM, so with all that said I was back to the original FREAKIN problem I thought it was from the very begining, the cooling fan is continually running, not going on shut down or automatic shutdown, unfortunately that cooling fan in the unit is not on its on circut so right now I have NAV, No Radio, which really sucks, does anyone have a fix to this problem??
 

·
Registered
Joined
·
10 Posts
Discussion Starter #5
Thanks guys, but the Stealership said its the overhead light module. Which was quoted at over 650 for the part. I asked if there is a fuse which I could pull every time to get out of the car to keep it from draining. First to see if that actually is the source of the drain, and second bc I have already spent 500 on a battery and two diagnostic tests, and I just paid tuition this semester.
If it is the overhead light control does anyone think an electrical shop could repair it, there is a great one in KC that has done some ecu changes for me in the past on a diff car. Or should I look at salvage yards?
 
1 - 6 of 6 Posts
Top