1994 325i Battery dies over night

[tucker07]

MY battery dies overnight, i charge the battery in after noon, and when i live my car over night, by the morning battery is dead already. Before, my battery would die pretty quick if i leave radio on. But this time the battery just dies over night, and its been happing 4 days in a row. I recently changed serpentine belt, maybe there something i did wrong, but im not sure. My own theory is that maybe its too cold, and im in need of a new battery or power alternator. Also people been suggesting to check the whole electrical system, is there anyway i can do it my self, to know whether my battery is bad or power alternator. thnx

[Jack Dabsy]

Firstly, have the Alternator tested... If this is ok then, something like a poor ground/earth is at fault, OR, a faulty security module or other simple wiring issue...

Go for the alternator first, just to eliminate it from our suspects ;-)

[tucker07]

i will do try it tommorow and let you know. I suspect maybe its fuses because, shortly i replace few fuses because the other was burned, those burned fuses caused my tail lights, dash board light and interior lights to go off. I also put new interior bulbs, ordered them from autohauz. Maybe if its fuses, then what do i do, because those fuses i got from bmw dealer. Also do you know how to check the power alt. and battery correctly, what numbers should i look for?

[tucker07]

so i think i found the problem, i recharge the battery again today, and started the car. i close all doors, and turned of all the lights, but then i decided to check trunk from a inside of a car, and i saw bulb still on, so for now i took it of, any suggestions why the bulb does not turn off in a trunk?

[Jack Dabsy]

Trunk-switch corroded or not adjusted correctly !
Well spotted !!

[tucker07]

Yep i found the problem its the trunk light, i took out bulb and so far for 2 days no problem with battery dieing.

[DickDonlevy]

Hi, I had exactly the same problem so I took the bulb out in the boot compartment and it's never gone flat since! Pity I didn't read your post earlier.