Alternator Light and Diode

[Steve Hummel]

situation; 1977 930 turbo, used primarily as a racecar, noted that battery under 12v, will not hold a charge, replaced, 12v+ at rest but 11v running, replaced alternator and voltage regulator, now 13v+ running, battery 12v+ at rest, system seems to be working, alternator light on all the time though, read forum, found diode in series with charging light, was a short circuit, noted that Porsche does not make a replacement, pulled low voltage diode from my racing box, light is now bright with key on but engine off but is still dim with the engine running and does not change brightness with RPM.

Then checked blue wire for short or resistance, performed continuity test from voltage regulator to bulb, was ok, then from voltage regulator to alternator, again ok. Double checked connections on alternator for rest of wires and re-tightened ground, seemed ok.

Any suggestions on where to look next?

Thanks,

Steve

[kwikt 911]

Check the small wire that goes to your starter. If dissconnected the light will stay on. At least that's what happened to my 911.