66 GTO Battery light
 

Working on an issue with a friends 66 GTO, with the key off and removed, the battery light stays on. After the engine starts, the light goes off. What does the light actually indicate.

Bad diode.

"Bill"!

I had that problem in a 65 and the voltage regulator was bad.

Well changed the alternator and also replaced the engine harness, old one looked nasty. Still have battery light with engine off, goes off when started and runs normally. Next I'll try a solid state voltage regulator.

Is this a restore or the light just come on out of the blue?? Try pulling batt wire and unplug the two wires going to the alt and see if light stays on or goes out????!!!!

"Bill"!

Mostly original tripower automatic, issue just occurred in the last week. I replaced the engine harness(M&H) because the old one was ratty looking and just replaced the alternator. Did a load test on the battery, shows good. Battery voltage is 12+. Problem before and after harness and alternator change. I'll pull the alternator wires with engine off and start it and see if the problem persists. Thanks for the suggestions.

Problem solved - put on a new alternator and the problem still there so I replaced the regulator with a solid state unit and that fixed it. I guessing it was was an incompatibility between newer alternators and original points type voltage regulator. I told my friend to monitor and let me know how it works out.