Howdy! My Amp light has been on for some time now, I have yet to have a problem with it. I've got a 69 Delta 88. Alternator does not look to be very old, battery is new, and the voltage regulator is new(er). I got back form a charging system test at Advance Auto: charging fine and doing fine, according to the guy that did the test, but when I looked up at the machine, I noticed the number under the word AMP on it said 4.5. Is that right? When I questioned the fellow, he said, "well, it seems low, but the test shows 13.[whatever] volts." Hmmm.....what should I be seeing and what will eventually happen to me with my car?

 

4.5 amps under a charge test? Not sure because don't those machines put different loads on the alternator to simulate real world effects? He SHOULD know however if an alternator was good or not, and not say it "seems" good. What kind of assurance it that? Take is someplace else. A bad alternator could be causing the idiot light to illuminate but it could also be a bad socket on the dash circuit board or even a soft short to ground allowing the lamp to illuminate. Is it lit bright or dim?

 

The amp light is kinda dim. never gets as bright as the others...doesn't seem so anyway.

 

A bad diode in the Alt will cause this.But it will still charge Larry

 

Diodes, according to the test, checked out.

 

Re-check that alternator someplace else, after you know for sure that it is good (or bad and you replaced it) if the lamp is still lit then you have a soft short someplace.