Author Topic: 1991 318is battery drain!! (Read 4647 times)

JASHAIRST · « **on:** January 20, 2009, 05:12:42 AM »

Ok this bad boy is causing greif..new battery if you let it sit for 2 days the battery is dead we replaced it again with a different one same thing. Need to know where to start looking. Checked the radio removed it to make sure it wasnt the problem. No lights are on and can not hear or see anything on or running.

ak96ss · « **Reply #1 on:** January 20, 2009, 06:08:58 AM »

This is the fun part about electrical problems - finding the source.

You'll have to hook an ammeter up at the battery and check the current drain with everything off. It's probably high - now go to the fuse box and start pulling fuses, checking each time you pull a fuse to see if the excessive drain is gone. When it disappears, you've found the culprit. Then it's just a matter of figuring out what on that circuit is not working right.

http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

twright · « **Reply #2 on:** January 20, 2009, 06:49:18 AM »

The other thing to check is to make sure that the alternator is charging. With the engine off, the battery voltage will be 12-13 volts. With the engine on, a good alternator will make the voltage go up by 1-2 volts.

monty23psk · « **Reply #3 on:** January 20, 2009, 09:21:31 AM »

With mine, it was the instrument cluster si batteries. Is your instrument cluster working, how about the SI lights. Do they stay on even with car off?

You will need to check alternator like stated above but the best is checking the fuses. You can use the ammeter or just a regular multi-meter. Thats how I did it. Believe it was fuse 21 or 22. Until the new SI board came in, I would unplug the fuse everytime I parked my car. I then lasted about 3 weeks with no issues.

JASHAIRST · « **Reply #4 on:** January 20, 2009, 01:32:37 PM »

thanks for the help now i have somewhere to start..did a little reading and maybe i can figure this one out.