Battery drain
Thread Starter
Junior Member
Joined: Jan 2007
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From: Des Moines Iowa
2002 C32 amg, 1998 328i
Battery drain
Does any one have schematics of the seat control module? or a test procedure to identify which one is draining current. Other than unplugging one at a time and wait 24 hours to see which one killed the battery. Thanks in advance.
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Joined: Jul 2007
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From: East Bay, Bay Area
2002 C32, 2012 S550
In my experience:
what a bad seat control module normally does is keep the command system fan on 24 hours.
Normally, once you shut off the car and pull out the key, the fan behind the navigation stays on for about 3-5 minutes(I think) and then shuts off automatically. When your seat control module is bad, it stays on all the time, thus draining your battery.
Trouble shooting:
Maybe try disconnecting one side(I think I have read that the passenger side goes bad most often) and then take out the key. Listen closely for the fan behind the Command screen. Wait 5 or so minutes and it should shut down. If it does, try disconnecting the other side.
Side note: Depending on how long you have this problem, it may also put extra strain on your alternator thus causing it to fail prematurely as well. Best to take care of it ASAP.
Good luck!!
what a bad seat control module normally does is keep the command system fan on 24 hours.
Normally, once you shut off the car and pull out the key, the fan behind the navigation stays on for about 3-5 minutes(I think) and then shuts off automatically. When your seat control module is bad, it stays on all the time, thus draining your battery.
Trouble shooting:
Maybe try disconnecting one side(I think I have read that the passenger side goes bad most often) and then take out the key. Listen closely for the fan behind the Command screen. Wait 5 or so minutes and it should shut down. If it does, try disconnecting the other side.
Side note: Depending on how long you have this problem, it may also put extra strain on your alternator thus causing it to fail prematurely as well. Best to take care of it ASAP.
Good luck!!
Thread Starter
Junior Member
Joined: Jan 2007
Posts: 66
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From: Des Moines Iowa
2002 C32 amg, 1998 328i
Thanks for the reply, I wish I had command, just the standard cassette and cd changer system. Both are unplugged tonight and I seel how it acts in the morning. I am worried about the battery being polished off as it is original. I have been unemployed all summer and I have to drive 300 miles to St Louis for 2 weeks of training and dont want any thing serious causing me problems on the road.
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LET C32 2002
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MBWorld Fanatic!
Joined: Dec 2007
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From: Corona, CA
03 g35 coupe...........02 c32 Sold
i checked the drive side today. The same solid brown and brown/red wires exist on the drive side too, separate from the other bundle of wires.
Note, you don't need to disconnect your battery terminal. All you need to do is disconnect the front harness to the seat control module. Its directly under your seat.
Its the solid brown and brown/red wires that causes the drain. you only need the solid brown wire to activate the control modules.
my diy for the lazy.
https://mbworld.org/forums/showthrea...55#post3068555
Note, you don't need to disconnect your battery terminal. All you need to do is disconnect the front harness to the seat control module. Its directly under your seat.
Its the solid brown and brown/red wires that causes the drain. you only need the solid brown wire to activate the control modules.
my diy for the lazy.
https://mbworld.org/forums/showthrea...55#post3068555
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Thread Starter
Junior Member
Joined: Jan 2007
Posts: 66
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From: Des Moines Iowa
2002 C32 amg, 1998 328i
just what the doctor ordered
Thanks for the schematics.
I hope to find the internal reason for the failure at the component level if possible. It would be cool if we could rebuild them or replace the bad circuit. For now Ill use the relay method of MR X
I hope to find the internal reason for the failure at the component level if possible. It would be cool if we could rebuild them or replace the bad circuit. For now Ill use the relay method of MR X
MBWorld Fanatic!
Joined: Dec 2007
Posts: 5,034
Likes: 6
From: Corona, CA
03 g35 coupe...........02 c32 Sold
i would rather just fix it with a $3 relay and some wires then pay for them to be rebuilt. I would imagine the cost would be a lot more then $20.
