Fried Headlights..please help

[jpabberton]

Last night my headlights and radio surged and the whole truck shut down. I lost both headlights, running lights and one turn signal. I also blew the fuse to the radio. The dome lights do work though.

I rewired my radio yesterday and put in a new ignition key switch. A few months ago I put in new Alt/AC and engine wiring harnesses, new HEI ignition, new alternator and new voltage regulator. Haven't had any problems until this.

Would the HEI or voltage regulator have anything to do with this? Any suggestions would be appreciated.

[glennhuff]

That's no fun at all. Glad you made it home OK. I don't know if these pickups have a mechanical voltage regulator. ???? Anyone... I always run an internally regulated alternator. If it is ,they can weld the output contacts shut causing an over voltage condition that could easily fry 30 year old electrical parts. This would explain why only the components that were being used were fried. With the engine off, use an ohmeter to measure resistance from the positive battery terminal to the large lug on the alternator. If you get no or very low resistance then the regulator is shot. On older cars with a generator this will cause the battery to try to turn the engine over using the generator as a motor. Don't know what this will do with an alternator, although I would suspect lots of smoke. Any way you look at it you will have to find what caused the overcurrent, and then check all of the electrical components and replace those that are fried. Good luck, and hope this helps.
glenn

[cdowns]

i'd say you've probably got a bad ground at the regulator

[jpabberton]

I get a reading of .1-.2 ohms measuring as you requested.

I have a stupid question: Do I need a voltage regulator AND a internally regulated alternator? And does the alternator need to be sized with the rating of the HEI?

The truck will turn over, so I think everything may be fine. Nothing seems smoked, so I'm stumped.

I appreciate all your help.

[68 Stepside]

First: No, you don't need a voltage regulator with an internally regulated alternator.
Second: I wouldn't drive the truck if that happened, it sure sounds like the regulator is stuck, making the alternator pump out a lot of volts.
Third: It is extremely simple to swap alternators over to internally regulated on these trucks, I'm sure someone will be able to tell you which wires to jump on the regulator plug. It's very straightforward.

Good luck.

[jpabberton]

Okay...I changed out the alternator to an internally regulated job...got the jumper cable, rubber boot, etc...and got rid of the external volage regulator.

Now she won't start. Could I have fried the HEI also when I fried the lights? Any other suggestions?

[jpabberton]

Finally got it running last night. It appears that the module in the HEI distributor failed. Luckily I had a lifetime warranty on the distributor, so they gave me another one. Fired right up after that.

What bothers me about the old distributor was the wiring. It came with a wire cover, and the replacement HEI didn't have one. When I took the wire cover off the bad HEI the three wires from the distributor were wrapped in electrical tape in various places. I would figure that at least the wires would be new. A friend told me that when they rebuild these distributors they only replace whats damaged and resell it.

So now, I have an internally regulated alternator, a remanufactured HEI and new battery cables. Hopefully this will solve the problems.