1988 300e battery light on and off
 

My battery light has come on and goes off occaisionally but when I measure what's happening at the battery I get a 13.7 volt rating when the engine is running and a 12.8 when the engine is off... there is no variation...

what else could be an indicator when the battery light goes on...

aren't these numbers pretty much where they ought to be?

Thanks

You need to visually inspect the voltage regulator brushes. If they are worn out they can go intermittent before they buy the farm. The other possibility is that a diode is failing, but before you worry about replacing the alternator check the regulator.

Yeah, the regulator is a 5-minute job, and a cheap repair.
I had the opposite problem; regulator/alternator failed, and the light never came on. I only discovered the problem when the lights dimmed to almost nothing.

DG

Brushes are easy to check. Safely elevate front of car enough so you can slide underneath. Alternator will be more to passenger side. Back side of alt. has 2 phillips screws. Remove both and out comes the volt. reg.

When new, the brushes on the volt. reg. are 1/2" long.

Checked brushes
 

They were good.... still getting consistent 13.7 reading with engine running but the light on the dash mostly stays on and only on occasion will it go off for a few seconds....

Anybody have any other thoughts?

Thanks

check all the ground straps