Marv

This is a re-post from last year. My problem is that the headlight switch shaft gets very warm/hot after about 15 minutes with the lights on. I now have a new switch but I'm wondering whether the switch shaft getting warm/hot is normal. Cheeseral wrote on 10/25/02:

-----PrarieShark is right, there's a small button/pin on the switch. If I remember correctly it's close to the dash on top of the switch as mounted. Disconnect the battery or your lights will be on the whole time and that switch gets hot pretty fast. Pull the switch to the on postition and press that button and the rod will come out easy. The tuff part will be finding that button with the dash all together. I did mine when I had the speedo/tach cluster out, it was easy then.--------

This, and a reply from an NCRS member that his 79 did this when new makes me think I might be trying to fix a non-existent problem. The switch functions smoothly and perfectly except that the shaft gets quite warm after about 15 minutes-whether the instrument panel lights are on, off or dimmed. I've checked the front harness for bad grounds and can find none. I'll check the rear harness tonight just in case. Last year I replaced the center cluster printed circuit board because the shaft would cool down if I dimmed/turned out the instrument lights and I knew those copper contacts were pretty wrinkled up which could produce a bad ground. Now, if the lights are on the shaft gets warm-period.

Now that weather allows us to drive more I'm hoping some folks will test their switch to see if they get warm/hot. I don't want to replace the switch needlessly so any experience or suggestions would be greatly appreciated.

Marv-

Crash80

My '80 headlight switch gets warm to varying degrees based on how dim I have my dash lights. I think this is fairly normal for this switch.

jetech

If your switch is like the one on my 77 it should get pretty warm because the shaft passes through a large ceramic insulator that protects the switch from heat generated by the panel light rheostat on the front of the switch. :cheers:

Yeller81USNRet

Same thing on my 81 the shaft get warm to the touch. Not hot but warm.
:steering:

Casper

The shaft on my 82's light switch gets hot to the touch also. It's been like that for about 5 years.

Corvette_fetish

I've never considered touching my shaft while driving my '79 to see how warm it feels. Perhaps I'll try it this weekend.

Marv

Thanks to all for the input on this. It may be normal but it may be one of those warning signs that something needs attention-as in: replace the switch. The heat just seems unusual. With the first Official Spring Weekend coming up maybe more of us will be cruising (with the lights on!) and will test for a hot switch shaft.

CVT4ME- before I changed the center cluster board the rheostat would also adjust the shaft heat level-but, the dimmer the lights, the cooler the shaft got. That's what got me going on the bad ground idea.

Corvette_fetish- I know, it was accidental on my part.

Checking the rear harness got delayed to Friday night for a Spring test drive on Saturday.

Marv-

DMONSVETTE

:conehead
:rofl:

Crash80

Marv, I can't remember which way mine gets hot. Mine might be the same as yours where the dimmer the lights, the cooler the switch. I will test and get back to you. I really don't think you have anything to worry about, of course I am one of those don't fix it 'till it is good and broke types. I want to get every dollars worth out my parts. Have you upgraded your headlights to halogens or anything like that. TheoUK and I had a discussion via private e-mail where he had an issue with halogens that caused him some headlight switch troubles. Here is part of the e-mail between us maybe something there will help you out.

From TheoUK:

"I don't want to scare you, but bearing in mind you have halogens, I'd have a little look at the state of the wiring up front. Make sure its all ok and not likely to be wearing away on the chassis like mine was. If you begin to notice that the lights blink on and off, especially when you're on high beam, then that will be the switch complaining about the extra current. Check the wattage written on the bulbs - if its much more than 60W per bulb, it might be worth installing relays. (That's if some kind person hasn't already - you never know your luck!) Also, grab the metal shaft of the light switch "pull", and see if it gets hot after running for a long time. I'm sorry, I'm not trying to get you worried, I know myself there's always something to worry about with a c3 anyway(!) but I just want to make sure no other poor unfortunate has to go thru all the repairs I've had to. Guess I learned from it...
If you do want to do the relay thing, I'm happy to help you thru it. Might well post my work on the forum when I'm done anyway..."

Anyway, I hope you resolve your issues and get your mind put to ease. Best of luck.

Marv

I have found the rare factory option where the rear harness ground was never bolted to the frame! The antenna ground strap lug was attached (with the original appearing bolt, nut and washers) to the ground wire from the rear harness but they were not then grounded to the frame. Oddly, the power antenna and radio have functioned just fine. The AIM and the GM Service Manual show diagrams of the grounding locations on the frame for power antenna and non-power but my frame has no hole in either location. I would guess this switch has been running hot since 1979. Properly grounded it has run cool after more than an hour of testing. So at least in my case a hot switch isn't a normal thing. Thanks to all for the feedback.

Marv-

Double Aught

:eek:

Tbone01

I have a 1979 c3 and shortly after I bought it, replaced the headlight switch. Re-wired (nicely) the tail lights (that someone else hacked up).
Now, the front head lights are blinking on and off after a few minutes being on. Can't locate a problem other than the switch is getting pretty warm. You spoke of adding relays, (although my lights are 35w) is this hard?

speedreed8

Circuit breaker in the switch is probably making them go on and off. I added 2 relays to mine. The switch now only activates the relays which carry all the current to the headlights straight off the alternator. They are much brighter now. I think danielstern has a kit for this. Danielsternlighting.com this is how i wired mine using danielstern diagram and parts.

Tbone01

Thanks for the link! I'll look into getting the kit.