Battery arcing out and draining battery
 

I recently purchased a 79 450 SEL and something is draining the battery...I was told by a friend that it might be a resister problem. The battery is arcing out.....can anyone tell what might be causing this and how can I fix it?

Thanks,

John

The battery itself could be bad, the top could be dirty and a small current if flowing across the top or the alternator internals could be bad.

Check those first then remove each fuse and put your DMM across the contacts. Measure the current in each circuit.

Maybe your trunk light is on.

Warren,

The battery is new.

Is there a resister that could cause battery drain....that's what I was told but that doesn't mean anything because the guy that told me this is a hobby type shade tree BMW mechanic......LOL

I had a drain in my Subaru last year. I finally got tired of jumping the thing. Measure your voltage across the pos and neg terminals after a charge. If you have a short somewhere you should see the voltage drop slowly.

I charged my battery fully and removed all the fuses in the fuse box. I attached the volt meter across the terminals and one by one inserted fuses. My dad watched as I got to my 4th fuse and the voltage started to drop. I left that fuse out as it wasn't worth tracking down the short. No more power door locks for me. No more dead battery either.

What do you mean "the battery is arcing out"? Do you see sparks somewhere?

Mike

I'm LOL.

Update, battery is not arcing
 

Sorry guys, the battery is just draining, not arcing out. My old lady neighbor that sold me the car told me that's what it was doing but it is not arcing....LOL. I finally got the car started after a very long charge and moved it to my garage.

Thanks for the tips on diagnosing the problem. After searching the net, it seems like one of the problems with Mercedes is battery drain. I found many topics on this problem.

Thanks again,

John