Service Battery Light

[goodespeler]

I just bought a 1983 320I two days ago for 800 bucks. When I turn the car off, the service Battery light comes on and it won't go off. It ends up draining my battery. When I turn the car on, it goes off. How can I fix this?

[goodespeler]

Could a bad alternator do this?

[wcleafs]

used
Very interesting fault, I dont quite understand why it is doing that but, your battery light comes on when it does not sense enough output form your alternator. the light is fed from the D+ out put of your alternator. It would appear that something is shorted out of your alternator. You may have to replace the alternator or localize what is causing the drain on your battery. The battery light is only connected to D+. I would disconnect your battery and then remove the cable from the alternator to the starter and check the state of that cable. I will research the wiring diagram and hopefully come up with something better

Cheers s

[goodespeler]

I hope it is just the alternator. He did say it wasn't recharging which means it does need to be replaced. I have a feeling after he replaces it, it will still stay on when the car is off. Do what you can oh mighty one...and make it a cheap and easy fix! I just had to dish out 700 for alternator, master cylinder, and fuse box replacement.