My alt. light stays on when the car is idiling.When i bring the r.p.m up,the light goes out.The alt.is charging though.Anyone have a idea why it does that?Ground problem?Thanks.

 

The alternator may not be charging sufficiently, as in there may be a leaky diode. I had that issue on my car back in the 90s.

I guess I should ask what type of alternator setup you have: factory setup or some sort of retrofit?

 

Its the factory set-up.All stock.

 

it could be charging fine and have a bad diode.

 

Take your alt. to a auto parts store and get it checked.

 

Is it an internal or external voltage regulator?

 

It has the internal voltage regulator.

 

Then yes, get the alternator checked.

 

Is the belt tight?

 

Yes,Belt is tight.Thanks for the info.everyone.