I have searched the FAQ's on this subject, but my symptoms are a bit different. With engine on and running, the generator light is off. Once I shutdown and remove the key, the light remains on and bright. Also, there is power to my radio that seems to be intermittent (on,off,on, off, etc.). If I remove the battery cable from the battery and then re-attach, the generator light goes off. I thought that maybe it was the ignition, until removing and restoring power to the electricsl system shuts the light off.
Is this the diode pack on the alternator or is it my regulator? Any ideas?

Do you have the internal or external voltage regulator?

Very nice car Marc!

Is that the one from craigslist a month or so back?

I especially like that Vikings front license plate!

I have the external regulator.

Thanks for the compliment 68tpls400. You have one sweet ride yourself. It is the one from craigslist. I bought it about 2 1/2 months ago. A corvette dealer had it on consignment and it had been sitting in his shop for over a year. My youngest son just started driving, so I gave him my truck and got something to mend my mid life crisis! I grew up in Bloomington from '76-'84. Big Vikes fan (don't tell anybody!).

http://www.pelicanparts.com/914/914qa/914Q_electrical_alternator.htm

Without the diodes functioning, current flows back from the battery and illuminates the lamp. Disconnecting the battery removes the current from that leg of the circuit, shutting the lamp off but potentially harming your regulator.

Thanks Vikki. I really appreciate the help.

You're welcome.

You know, there is one new strange twist to my symptoms. With the car running, the GEN light is off. When I honk the horn, the GEN light goes on for the duration of the honk. So when I turn the car off, the GEN light is on. If I honk the horn with the car off, the GEN light goes off. Does anybody remember that movie with the '58 Plymouth Fury Christine? Too bad my car doesn't fix itself!

You're drawing a high amp load from the battery while the alternator is idle. Should do the same if you turn the blower on high and the headlights and high beams on.

Marc,

I recently had some problems on my electrical system (Read post on voltage regulator). Vikki was nice enough to provide links to some good wiring diagrams in the thread you may want to check out. The horn relay, regulator, alternator output and battery are all connected via a junction block. The GEN lamp is connected to the Brown wire coming off the voltage regulator. Take a multimeter and check all of your wires and grounds if you can before you change out anything. Make sure the ground between the battery, alternator and regulator is good (Zero Ohms). Another thing to check is the output of the alternator when the car is running using the voltmeter across the battery terminals or looking at a volt gauge in the car if you have one. This may also help indicate if the alternator is having some issues. Otherwise either the alternator or regulator are the likely culprits and are easy and cheap parts to replace, then again there is something to be said for just hitting the horn after you shut off the car and call it a day

The car looks great!I remember looking at it on Ebay when I was searching, I just couldn’t live without getting a convertible and ended up with a red 68 400 about a month ago.

I know that it's been about a month since this thread was started, but in the event that anybody stumbles across it, I wanted to post the result of my findings. With the engine running, I was reading 17-18 volts at the alternator and the battery! When running at higher RPM's on the road, my aftermarket voltmeter gage was pegging out at 18+ volts. I took the alternator into the auto part store for a test. The computerized diagnostic machine said that the alternator passed all tests. It seems strange that 17 or 18 volts would be normal output. Does this sound normal to you guys? Anyways, I purchased a new voltage regulator, installed it and the system seems good. Volt gage never exceeds 15 volts. Also, my GEN light now goes out at shutdown. I don't even have to honk the horn anymore!!