Join Date: Mar 2002
Location: Austin, TX, USA
Yes. If you disconnected the big red wire to the alternator and the light did not go out, the alternator and diodes are fine. If the Voltage regualtor shows a draw with the key off, then you may have found the problem. Just for kicks, you might try disconnecting the fuse panel plug (under the hood near the stearing column on the firewall) with the regulator hooked up and see if the light is still on. If so, then your diagnosis is correct. There is a bolt in the center of the fuse panel plug. Remove it and the harness will come unplugged.
Sometimes the relay contacts in the regulator will weld shut causing a short or will not charge. You might also examine the horn relay connections to make sure two wires haven't come in contact with one another. The horn relay also serves as a terminal block for main power feeds.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI