Voltage regulator trouble?

Started by 2danreed, October 25, 2019, 05:22:32 PM

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I just replaced the alternator and voltage regulator on my "64 Cadillac. Everything seems to be charging correctly (12 volts at bat. with car off, 13-14 volts when the car is running) Odd problem is that the volt. reg. is causing the GEN light to come on while driving at certain rpms, it blinks on as I slow to a stop. Then blinks on again as I take off from a stop, but stays off while cruising speed. Then when I park and turn the car off the GEN light comes on! I can only get it to go off if I disconnect the four wire plug on the voltage regulator. What's the deal?
Dan Reed

Bobby B

Maybe the VR needs to be adjusted? "New" Alternator could have a bad diode or dead spot once it heats up. All this stuff is from China now and the quality of the rectifiers are terrible. They will trash a computer in a modern car.
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH


might want to check with Brillman. I bought a high quality made in the USA regulator and other parts from them. Mine was $96.00.  Not cheap but good quality. Working perfectly after 500 miles.


Bob R.
1940 LaSalle 5227 Coupe(purchased May 2016)
1985 Lincoln Town Car Signature Series. Bought New.


Thanks guys.  I decided to go with an upgrade to an internally regulated 3-wire alternator. That did the trick. Its charging correctly and the GEN light comes on only momentarily at startup and goes out when running and when the car is turned off. That external regulator must have been the culprit.
Dan Reed