Smoothy

I posted this in the tech forum, but thought that it maybe a common problem and thought I would get some help here.

I have a 2002 C320 sedan.

I have a battery draining problem. I had a similar problem a few years back under warranty and they told me it was the seat and they fixed it. Now, the problem is back but not under warranty. I checked all the fuses and I couldn't find anything with significant drain. I removed the fuse that powers the seat also, and that still has not prevented the battery from dying over night. If anyone knows how to check the seat, and what to check/replace, any help would be much appreciated.

Does anyone know if this is a common problem?

MB-JIM

If your battery is 3 0r 4 years old it is probably at the end of its life.

mleskovar

Someone posted a very detailed method of troubleshooting a battery drain problem, I think a couple of years ago. It involved using a volt meter and measuring current draw as you unplugged major systems in the car.

rtking

I have this problem in my 2002 C230 Coupe. Everything was fine, then one day the battery was dead. Fine, I change the battery with a new one and a week later, it's dead again. I charge the battery and a week of not driving it, it's dead. I took it to Mercedes for diagnosis and $400 later, they tell me that everything is OK and they can't find a problem. I should have just thrown that $400 out the window for all the good that did me.

I just went out to Sears and bought an electronic trickle charger for $40. When I don't drive the car, I just plug it in and let the trickle charger determine when it needs to charge the battery. When I want to drive the car, I just unplug the trickle charger and go. Or if I drive the car more frequently than once every other week, then it's fine...

Bob

tifosiv122

I have an '03 with just over 50K on it. Up until I moved to Michigan (about 1.5 years ago) I had no battery issues. The first winter I was here my car died, they replaced the battery under warranty. This winter it died again, and they blamed it on a faulty regulator or resistor or something...$450 later. Well, here we are, three days after the service and my car is showing signs of a low battery...the red indicator. I'm bringing it in tomorrow. I know they are going to blame my aftermarket stuff, but this is really pissing me off. At least I'm not the only one with problems.

Erik

tifosiv122

Got a call from the dealer, they claim its a bad alternator, but say "we checked it and it was fine 2 days ago". Yeah right, whatever.

Erik

otyaglo

I've had similar issue with my c240. I came from my 4 week vacation - battery was completely dead.

However, here is what I noticed few days later:
A car may turn on rear interior light! I could not believe it myself.

So I just removed rear interior light module, disconnected the harness and place it back.

How to tell if this is your case:
If you car get wet overnight and early morning you see dry spot on roof in a rear - you have the same issue. (Lamp produces some heat that keeps area next to it dry outside)

Hope this will be some helpful

wingless

A Midtronics Battery Tester is the tool to quantify the battery condition. It will define the state of charge and the battery capacity. This will permit an accurate judgement of the battery health.

The "dark current" may be measured using a multimeter.

The charger output and components may also be measured and compared to standards.

Battery problems suck, but may be resolved using normal analysis and by following procedures.

Smoothy

It was my other seat, the passenger side that was draining. The problem found, just need a new seat control module.

therock2689

Hey, i have been having teh same problem in my 2k C230. I took it in not to teh dealer but another bez specialist, and he said it was something with the soem SAM units or something like that. Anyway, if it is when u turn the key, it may be that, just take to to a reliable benz specialist not the dealer, they just, well u know what in the behind.

mpalsal

Same as my car, 2002 c320. Bought Nov 01, 2001, at 70,000 miles, problem started on Jan 2nd, 2006. Battery dead, AAA jumped start. Jan 12, battery dead, jumped start by AAA, took it to Rusnak, changed seat control (driver side) = $650. Feb 28th, battery dead, AAA jumped start, took it back to Rusnak, now it is the PASSENGER side seat control, another $650. Last Saturday, Mar 11, battery dead again, AAA jumped. Took the car back to Rusnak this morning, overhead control module (by the sunroof). I complained to my service advisor that this is a known problem for 2001 and 2002 models, why no recall? He called me back today to let me know that the part (overhead control module) will be free but labor cost $150. I am still wonder why there will be no charge for my part? He was ambiguous on the reason citing that the service manager spoke directly to MBZ of my complaint. I am not sure if this will solve the problem. Will pick up t he car tomorrow but will keep my finger crossed. I beleive there is a detailed post of this issue somewere on this board.

mp

Moviela

Sure glad I got the manual seats!

TammieGray

I am having the same issue with my 01 c320. This is the first time I've had this problem. I've replaced the battery and it still drained DRY within one week.

I have noticed that the COMAND panel (?) on the instrument panel stays light all the time.

Also, during the past two weeks I've noticed that the auto climate control has trouble starting. I normally have to drive approx 20 minutes before it starts - which has been awful in the 110 degree heat.

Finally - the moonroof has been acting up; going back an inch at a time.

Should I try to unhook the power seats, as I've heard this is a common problem???...

UGH....don't tell me I have to go see the "helpful" technician....

atc9443

I'm having the same battery drain problem, brand new battery got replaced...I did all the re-syncing of the electricals that was needed to be done, but still, a week later car would not start due to battery. The only thing I notice now is that the comand unit's fan still runs after car is shut off, and i think that is the cause of the drain...I also noticed that the when the comand unit is on the red led does not come on any more...does anyone have any inputs to this situation? The damn stealership wants $3900.00 to replace the unit. They are crazy.

raymond g-

Tammie - check the STICKY for technique to resynch the roof

if you disconnect the power seat module and the accelerated discharge
goes away, then yes, the cause it the infamous seat module. if not, then
the cause is something else

QQQ

My MY01 C320 has same problem... first they replace the battery and still doesn't work. Bulbs are blown frequently and then your seats go wonky... like not retrieving the last saved seat position or the mirrors move while driving... eventually batt drained and the dealer took a voltmeter all over and found the passenger seat module draining batt... replaced and all the other problems go away.

raklert

hPPEN TO ME TO it was both of the seat control module cost me a grand for nothing.