'88 Brake & Alternator Dash Light came on today. Is the battery shorting or the alternator going south?? If disconnect battery and engines continues to run it's the battery if engine dies it's the alternator? Thanks in advance

 

Possiblity that either one or both the alternator or battery are dying. Either one faulty can cause failure in the other. Take 'em both off and then down to the local chain auto parts store (Autozone, etc.) and have them both load tested. Then go from there.

Mike in AR

 

I would guess alternator, as an alternator can carry a dead battery. Unless you were at idle.

Based on your experiment yes, thats correct. Howver I wouldn't suggest taking the battery away from the alternator with the engine running, they dont like that.

 

alternator
this is the warning that it is going out (brushes are worn)

find the local rebuilder and have him fix you up
or
go to roger browns site and he has the kits to do it yourself
just dont trade your original parts in for a rebuilt one (NAPA, Checkers, etc)
they are usually junk

 

Yeah, I would fix the alternator asap so you don't kill the battery also.