I posted a thread a couple of months ago about burning out my headlights, well now I have now done it again. I have been troubleshooting and verifying the wiring and recently put a NOS switch in the truck because it had an aftermarket installed. All of the wiring matches the wiring diagram but I once again I burned out both low beams at the same time. This was the scenario: I replaced the headlights and swith a few weeks ago and have driven the truck at night on several occassions during that time with no problems. Tonight I pulled it out of the garage and let it sit at a high idle for ~15 minutes because it had been sitting for a few days. I get in it to take a ride, turn on the lights, get about two blocks from the house when both headlights go out. I also noticed one of the two front running lights burned out tonight. The truck is completely stock and has not been modified. It is a 50' model with a flathead six. The only modification is an 8 Volt tractor batterry that my grandfather wanted to put in instead of a 6 volt. I have also noticed that the power feed to and from the light switch gets fairly warm when the lights are on.

Is this problem caused by the 8 volt??
Am I having a generator problem or a voltage regulator problem with high spikes as was mentioned in the other thread on generators vs. alternators??

Any help would be appreciated, I'm getting frustrated and also afraid to leave the house in it at night.

 

I think ur over Volting ur Ele system buy the sounds of it.. could be the gen is oervolting and burning out the lights.. It my also take out ur coil in time and could couse a Ele fire( wires getting warm) take the gen to a NAPA to have it tested.... Sadly it might be time for a 12vdc Conversion....

 

Thanks for the info, I'm doing my best to keep it original. Everything is pretty much stock except for the wheels and I'm working on finding originals to replace them.

 

Best of luck.. Go to ur Local NAPA and if the gen a problem thay should be able to point to a good rebuild shop for it..

 

The conversion to an 8V battery would definitely be a suspect for me if I was in your shoes. I think you should start with some measurements before tearing things apart and making changes.

First thing I would do is a simple test.

1. Get a DC voltmeter - it doesn't have to be anything fancy. Radio Shack has one (Catalog # 22-218) for about $15.
2. Run a temporary wire from the headlight switch power terminal to the minus terminal on your meter.
3. Run the plus terminal of your meter to the battery plus terminal using an extension wire.
4. With the lights on and the motor at idle, you should see something in the range of 6.0 to 7.5 Volts. I bet you see something higher with that 8V battery installation.

If you see a higher voltage, it's going to be hard on all your light bulbs and, possibly, other accessories. If you currently (pardon the pun) don't have any trouble starting the engine (it turns over fast when starting), I'd seriously consider going back to the original 6V battery. It's also likely that the voltage regulator has been adjusted when the 8V battery was installed to have the generator put out a higher voltage. If you switch back to 6V, make sure you have the voltage regulator adjusted as well.

Good luck with the problem - hope you get it solved!

 

I'm pretty sure I found the problem. I currently have an 8 volt battery, when the truck was not running I had 8.4 volts to the light switch. When I started the truck up it went up to 12.75 volts. I don't know if this is just a coencidence(sp?) or if at some point a previous owner jacked the regulator up to try to run a 12 volt battery. I read the manual on how to test the regulator but I don't have the reostats it requires. I can't decide whether to just adjust the voltage back down and not worry about the voltage cut out switch or go ahead and just buy another regulator. A new regulator is only $33 so I am considering purchasing a new one. Does anyone have any experience with a new regulator, does it still require testing and adjustment or will it be ready to go?? I"m also going to switch back to a 6 volt battery so the regulator can be set to original specs.

 

Greg,

Glad you found the high voltage problem. I agree with you - that is definitely an issue for lamps, and could cause other electrical accessory problems. I bet you are on the nose as far as the high voltage regulator output goes as well. Either it was adjusted, or maybe it's a 12V unit that's been swapped in?

I would also keep in mind that the instruments have been running with that 12.75V supply. They might be 1) the original 6V units unmodified, 2) the original 6V units adjusted (rigged as 'fenders says?) to work with 12V, or 2) 12V units swapped in at some point.

My new regulator (12V) checked out OK right from the vendor, but I can't speak for anyone else that might have had to adjust theirs after buying it. I did the checks on the bench myself, 'cuz I got a lot of electrical and electronics "junk" lying around. I wonder if one of the local parts places like NAPA or AutoZone would be able to test the new regulator for you? I suspect they might look at it like it was from Mars or something.

 

I had a voltage regulator from my 65 Mustang tested at a NAPA store a couple of years ago. The test equipment they used appeared to be pretty old so I don't know if all NAPA stores still have the equipment...

Vern

 

I talked to Auto Zone and they didn't have the right equipment to test it. They did have the part listed but couldn't test it. I"ll try NAPA next.

 

It sounds like you have a 12 Volt system. I would get a 12 Volt battery and 12 Volt lamps all around; it sounds like they need to be replaced anyway. You will need a resistance in series with each of your gauges, except the ammeter. The voltage drop resistors can be had at auto part stores or on ebay. The ammeter inductively senses the direction of the current, so it will run fine without modification.

 

I think the problem is with the alternator (or generator). If it was original, it should put out 7.0-7.5. If you're getting over twelve, then it is either a 12 volt model or an original that has had some customizing done to it. I would find a generator/starter shop to check it out for you. Good luck, John