Battery died overnight
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Joined: Aug 2012
Posts: 194
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C63 P31, C320
Battery died overnight
Hello, I have an issue with one of my cars. The battery just died overnight.
To the point where i couldn't even unlock my door. I drove it yesterday at 6pm.
I already had both the seat controller modules unplugged.
Any idea of what else could be causing the battery drain?
To the point where i couldn't even unlock my door. I drove it yesterday at 6pm.
I already had both the seat controller modules unplugged.
Any idea of what else could be causing the battery drain?
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Joined: Sep 2011
Posts: 1,657
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From: Austin, TX
2005 C230K(sold), Mk7 Jetta
Faulty amp maybe? Check this thread: https://mbworld.org/forums/c-class-w...ched-fuse.html
MBWorld Fanatic!
Joined: Jan 2005
Posts: 2,848
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From: Orange County
2005 C Wagon (No snickering please!)
Could be any number of modules on the CANbus that are supposed to wake up when the car is turned on. The seat modules and the power amp (with premium audio) are obvious choices having had design errors in their manufacture.
Are you sure the seat modules are still unplugged? Helpful mechanic or car wash might have reconnected them.
Faced with your situation, you really don't know who the bad actor is at the moment. Could be a flat battery. If you determine it is bad on a tester, buy an OEM battery because aftermarket batteries are too small to power all the consumers in the car.
Is your alternator and regulator still working? A competent electric shop can test it on the car.
If there is a consumer that did not go to sleep when you locked the car you will need an ammeter to measure battery current. Remove the negative cable and connect the meter on the ten amp scale. The car should draw .050 to .100 A when you have the car locked.
It may take a few minutes for the car to "sleep" after locking because of lighting and what not. If the car remains at a higher current like a few amps, the glove box light might be on. If you cannot see an obvious troublemaker, use the fuse chart and remove fuses one at a time and look for the current to drop to less than .100 amp.
Good luck.
Are you sure the seat modules are still unplugged? Helpful mechanic or car wash might have reconnected them.
Faced with your situation, you really don't know who the bad actor is at the moment. Could be a flat battery. If you determine it is bad on a tester, buy an OEM battery because aftermarket batteries are too small to power all the consumers in the car.
Is your alternator and regulator still working? A competent electric shop can test it on the car.
If there is a consumer that did not go to sleep when you locked the car you will need an ammeter to measure battery current. Remove the negative cable and connect the meter on the ten amp scale. The car should draw .050 to .100 A when you have the car locked.
It may take a few minutes for the car to "sleep" after locking because of lighting and what not. If the car remains at a higher current like a few amps, the glove box light might be on. If you cannot see an obvious troublemaker, use the fuse chart and remove fuses one at a time and look for the current to drop to less than .100 amp.
Good luck.
