911 sc charging system, need more help
 

Guys,
Thanks for the continued help as I debug this problem. Some background, Alt has been rebuilt and I had no problems for some time. Now no charging again. I have heard that if the charge light in the instrument cluster does not light up with the switch in the on position, the problem is around the wiring, ignition switch, or bulb. I have now replaced the ignition switch. The light still does not work in the on position. It does work as soon as you move the key to the next position and engage the starter. The light stays on in that position until the engine starts. The charge light has 4 wires to it being a light blue and a dark blue to the bottom of the bulb socket and two red wires to the top of the socket. One red wire has a green stripe. Can anyone tell me which wire I need to be measuring for power with the switch in the on position. Can anyone theorize why the light works with starter turning but not in the on position. Thanks for the continued support.

One more piece of information, all wires are in good shape. All connections look very good with no corrosion.

does car altenator have internal voltage regulator? if it does do you have a resistor between charge indicator light bulb? regards tom

What year/Model?

The car is a 1982 SC. It does have an internal voltage regulator.

Thanks for the help.

Bad Internal regulator. Check for power at the bulb Blue wire. If there is no power the regulator may be the cause.