I finally got the vintage air installed in the 69!! Everything worked great yesterday, but on the way to work this morning my GEN light pops on and my ammeter gauge slides to about 0. The first thing I thought was that the belt came off, but when I popped the hood the belt looked good and the wires were securly plugged into the alternator.

From what I understand, the GEN light stays off if it gets voltage from the iginition switch and the alternator, so I must have lost voltage from the alternator as the car was still running.

I'm not sure if the voltage regulator plays any role in this. When I first restored the car I used a Wells unit which died in about six months. Then I replaced it with the "premium" Napa unit, which died in about 4 months. I don't know if those were bad units or if I have a voltage regulator killing electrical problem. When the other two voltage regulators went bad the GEN light never came on, the system just stopped charging.

Anyway....Anyone have any tips to troubleshooting this? Could it be my alternator died(it is the original unit rebuilt/rewound to make 100 amps), or should I check something else?

I talked to the Napa manager where I got my regulators. He has a 70 SS Chevelle that he drives daily. He says that the Napa regulators go out every couple months on his car, so I guess I don't have a voltage regulator killing electrical problem.

I hate to hear that about the NAPA regs. In the past 3 years I've went through 2 Advance Auto el cheapo's ($12) and recently picked a $45.00 NAPA version. I hope it last longer than a couple of months. I don't have an answer for you but if mine goes out again I'm going to replace the alternator. I had it tested awhile back and it was okay. Maybe take your alt. in for a test. Good Luck

Edit: The last time my reg. went out the Gen light never came on and the battery went dead. Replaced reg. back in business (for now).

My alternator is the original alternator "rewound" to put out more amps. My theory is that since that case/fan wasn't meant to generate that kind of power it probably ran too hot and killed itself. I am going to buy a 12SI and try it out!!

P.S. It does kind of irk me to know of the low quality voltage regulators out there. Hopefully the internal regualtor will be of better quality.

I got some more info on the regulator problem!

OK...back in the day they made regulators to work with up to 63 amp alternators, but now the regulators that they make(Napa) are only rated for something like 47 amps. Since most of our cars with our new fangled gadgets draw more than the 47 amps, we wear them out over time(a short time in some cases)!!

At least that's what the Napa store manager told me. :D

New 12SI alternator and everything is good! I'm glad to be able to remove that old external voltage regulator!!

Regulators don't have much to do with what comes out of the alternator as far as amps. They only control the alternator.
My Wells regulator has a guarantee on it. I would have taken it back. I still like the Delco units best of all but the price on them is a little high.