Gen light on after Alternator rebuild

[White75]

After my Gen light came on my 78, I bought a rebuild kit online and replaced the brushes (one which was broken) and the regulator. I took it out for a drive this weekend and the light came back on after starting it. The battery was charged because it cranked over like normal but the light was on the entire drive, but dimming at higher RPMs. The gauge needle was right in the middle though which makes me believe that it was charging but I don't want to take a longer drive and have her die on me.
The questions I have are did I miss something during the rebuild? How do I check what the voltages are at the alternator and what should they be? Is there some other regulator that may be bad and therefore throwing the light?
Thanks!

 

[Yoda]

I had pretty much the same experience with my 81 a few years ago. Only my alternator was fine, of course I replaced it not knowing it at the time... What I found was the connector I think it is a 2 wire that plugs into the alternator was bad.. The way I found it was about the third time I was taking out the alternator to be tested... one of the wires pulled out of the plug... New Plug, cleaned wires installed in plug, plugged back into the alternator and I haven't had any problems in years now

Good luck

Bud

 

[BigJimZ16]

After my Gen light came on my 78, I bought a rebuild kit online and replaced the brushes (one which was broken) and the regulator. I took it out for a drive this weekend and the light came back on after starting it. The battery was charged because it cranked over like normal but the light was on the entire drive, but dimming at higher RPMs. The gauge needle was right in the middle though which makes me believe that it was charging but I don't want to take a longer drive and have her die on me.
The questions I have are did I miss something during the rebuild? How do I check what the voltages are at the alternator and what should they be? Is there some other regulator that may be bad and therefore throwing the light?
Thanks!

Did you change the "diode-trio" during the rebuild?? If not, it could be your problem. The pupose of the diode-trio is to sum the values of the three phases of the alternator and turn the light on when one is missing.

 

[White75]

Did you change the "diode-trio" during the rebuild?? If not, it could be your problem. The pupose of the diode-trio is to sum the values of the three phases of the alternator and turn the light on when one is missing.

yeah I did replace that as well (forgot to mention that in the OP)

 

[White75]

I had pretty much the same experience with my 81 a few years ago. Only my alternator was fine, of course I replaced it not knowing it at the time... What I found was the connector I think it is a 2 wire that plugs into the alternator was bad.. The way I found it was about the third time I was taking out the alternator to be tested... one of the wires pulled out of the plug... New Plug, cleaned wires installed in plug, plugged back into the alternator and I haven't had any problems in years now

Good luck

Bud

I'll definitely check that out. I cleaned some nasty old grease out of the plug but maybe not well enough (or too well).