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Old 10-13-2012, 11:05 AM
Bimmerkid325i Bimmerkid325i is offline
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Location: California
Join Date: Nov 2006
Posts: 83
Mein Auto: 1991 BMW 325i E30
Originally Posted by BMWFatherFigure View Post
Thanks for the good word, BMWEnthus. As the problem seems to be related to Fuse 21 only I would be going for everything connected to that circuit big time. Do you turn the radio down or fully off? If you used to turn it off but now only down B4 taking the key out it could be that the radio was put on permanent power in error - just a thought. I guess that if fuse 21 is pulled the battery stays good for a week (or at least several days)? If this is the case you will have to isolate the items on the fuse one at at time. Slow I know but when you find the faulty unit there will be no doubt and it is cost free.

Battery terminal/wire and connection corrosion should be fixed asap. A strong solution of bi carbonate of soda in hot water will nuturalise the acid growths and then clean and test/inspect all joints, terminals and earths.

Globe/bulb removal will stop any drain from a light, again check for corrosion. How is your charging voltage?
The problem was notice and tracked down this last Tuesday 10/9/12 and it hasn't been drained since I pulled fuse 21.

I'll be able to work on it more tomorrow. I'm working almost every day so my free time to spend on it is limited. I will keep you updated. As far as I know I have good charging (since its been driven every day since diagnosis and no draining or dead battery) but I will check tomorrow and get a definite figure on the charging voltage. Ive unplugged (by the connector) both overhead lights, truck light, active check control (overhead), glove box light, and radio faceplate. All these didn't cause the battery drain because there was little to no change in the amount of draining. When I removed the radio faceplate I noticed that the drain was less then when it was on. Meaning? I am going to pull off the digital clock tomorrow to check that. The flashlight connection in the glovebox shouldn't be a problem I'd think because I don't have the flashlight attached. :/ next would be to pull off the cluster and unplug the connection to the fuel economy gauge and service interval indicator. Also where is the ignition key/seat belt warning? Anything else on this circuit I should check. I have an electrical diagram in the car (not with me right now) and will double check myself. Thank you for all the help!!
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