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DISCUSSION => Electrical => Topic started by: manuel on May 02, 2007, 03:30:11 AM

Title: battery drains
Post by: manuel on May 02, 2007, 03:30:11 AM

Hi, about 2 weeks ago I installed a new battery in my 318is, after 4 days without using the car, the battery drains completely, If I jump start the car, it starts ok, any idea where I should start looking?.  It has happened twice already.

Title: battery drains
Post by: e9nine on May 02, 2007, 07:56:05 AM

There's a popular technique to checking this. Hook up an ammeter to the battery. Start pulling fuses one by one. When the voltage drops, you have found the culprit circuit. You can actually obtain more in-depth instructions from any electrical book or simply google search as this is generic to all cars for the most part.

Some issues I have experienced causing battery drain on the e30 in the past:
Faulty trunk light switch
Corrupt SI board circuitry
Improperly installed alarm

Good luck.

Title: battery drains
Post by: romkasponka on May 02, 2007, 10:08:36 AM

I had the same problem, it was trunk light switch...

Title: battery drains
Post by: b318isp on May 02, 2007, 11:50:16 AM

Is the alternator putting out >14 volts? Put a voltmeter across the battery with the engine running. Brushes could be ending their life...

Title: battery drains
Post by: manuel on May 08, 2007, 02:42:55 AM

Thanks guys, it was a faulty trunk light