I'm going to guess smoke is bad!

[377]

I'm hoping somebody might be able to help me out here. I'm building a new rig and have run into a major problem with my headlights. First I'll give you some details on my project. The body is a bronco design fiberglass tube on a 1974 frame. Wiring harness is a new American Autowire Harness and it has a Toms Bronco Parts Headlight Harness/Relay. When I initially installed everything there were no problems at all everything worked as it should. One day I'm messing around and hit the dimmer switch and no bright ligh indicator. So I walk around to the front and no power at any of the headlight connectors. I check my ground and power feed for my headlight harness everything was fine. So today I take out the new headlight switch and replace it. Everything is working as it should be. So I stick it back in dash and it's not working again. So I jiggle the headlight switch knob I notice my high beam indicator comes on and I have headlights. I also notice while doing this a noise coming from where my headlight relays are mounted. Kinda of a click noise. So I continue jiggling and it keeps going on and off. During my last session of jiggling I noticed a tiny bit of smoke come out of my vent area. I immediately disconnected the battery and removed the switch from the dash. Once the switch was out of the dash I hooked the battery back up and jiggle the switch. It didn't do anything at all. I inspected the wiring harness for any signs of melted wires and didn't find anything. The one constant with both switches and whether headlights worked or didn't is my tail lights,courtesy lights and gauge lights work fine. Based on the clicking noise coming from the relay mounting area I really suspect something going on there and possible back feeding from there caused my tiny smoke show? I also noticed when the headlights aren't working the high beam indicator light has a very very faint glow no matter what position the dimmer is in. This also makes me suspect some kind of back feed also? If anyone has run into this kinda problem before and could give me some guidance I'd greatly appreciate it. This project is supposed to be an enjoyable retirement project and has turned into something that just pisses me off! For what it's worth this isn't the first from the ground up vehicle I've built. I have just had more problems with this thing then all the other rigs I have built. Sorry for the rant this thing has just come to the point of being more annoying then anything. Thank you in advance for any help you can give me..

 

[Jfryjfry]

The clicks are the relays working as they receive and lose power as you wiggle the switch. The high beams are, I believe, divorced from the headlight and are completely isolated to the dimmer switch.

It definitely sounds like your switch has a problem and maybe your dimmer switch but they could be messed up because of bad grounds. With the fiberglass tub, I’d imagine you need to make double sure you have adequate (and clean) grounding. I don’t know how yours works, but several things ground to the dash. Which grounds through the mounts to the body and then to the battery. If you have a metal dash, run a good, large ground wire from the dash to the battery.

 

[377]

I think the ground makes sense because in the dash and wiggling the switch worked, took it out and nothing. The part that throws me off when I put the switch in just hanging out of the dash initially it and the dimmer worked. I’m also going to take a quick look at the headlight output wire leaving the switch to make sure it’s good. Because every other function in the switch works correctly. I will definitely run a ground to the battery from the actual dash. I never gave thought to grounding the actual dash because all the stuff in it that I knew needed grounds all got grounds going to two ground blocks that go to the chassis. Thank you for the help it’s nice to have someone thinking thats not irritated by all the little bugs!

 

[gnpenning]

I think the fact you have a light glow in the high beam indicator light when off points to a ground issue.

 

[377]

Yea I really think it is a ground issue. I checked both the headlight input and output wires and they are hot like they’re supposed to be. I’m at a loss on my grounds though. The headlight connectors are both ground to the chassis and both grounds for the headlight harness/relays are grounded to a grounding block that grounds to battery. The battery is grounded to the chassis. My grounding points on the chassis are 1/2” thick ,3/8 threaded blocks welded to the chassis.

 

[gnpenning]

What happened when you ran a direct ground for the dash any changes?

 

[377]

I ran a line to the dash directly from the negative distribution block to the dash with no change. I am at a loss as what to do.

 

[bmc69]

You might need some of this....I use a lot of it working on the Triumph...

 

[gnpenning]

How are the marker/turn lights and headlights grounded? Have you double checked them.

To be clear when I asked about checking grounds I'm talking about checking all connection and making sure no pins have been pushed back in the connectors, also checking continunity to the battery. Have you by passed the headlight relay harness yet? Wiggle test small sections of harness looking for changes.

You mentioned smoke came out the vent, which side?

 

[Jfryjfry]

You jiggling the knob and it causing things to come on and off is a strong indication of something loose/broken in the switch or possibly the wiring at the switch.

 

[377]

I haven’t checked the actual physical connections of the grounds. I’ll check those for sure. As far as the feed connector be loose or damaged I wondered about that. I checked it with a test light and had current. I put the switch back on and jiggled the wire and nothing. The smoke came up pretty much directly from above the headlight switch. I’m almost certain I heard an arc or two from the switch when the smoke appeared and I was jiggling the switch. I could find any evidence of the arcs on my switch or connector though.

 

[DirtDonk]

Next time you have the switch out, which should be soon anyway;D smell the switch.
You said you did not see any indication of burned wires, but the switch can have issues inside.

Did you say you tried two separate switches too? Or just mounted and dismounted from the dash with the same switch?
As someone said, you jiggling the switch causing it to work is a direct indicator that it's either the switch or something else that you're jiggling like the wires and/or connections.

You can remove the main connector and jumper the power wire to various outputs to see what happens. You lose the protection from the circuit breaker, so do not do this test lightly, but it might tell you something.

If only the one switch, replace it. It's one time when throwing a part at a problem might be justified. If your new one still does not work, then keep the first one as a spare. Then again, it would not be the first time in the modern era that more than one part was bad right out of the box. And a light switch would be a perfect candidate.

The headlight switch itself does not need a ground to the dash. It's only an open/close kind of a switch (other than the rheostat for the dash lights) so only the circuits themselves require the ground for the load to function.

Regarding the high/low switch (another very common failure point and not to be ignored) only one output wire comes from the headlight switch to the floor dimmer. From there it goes either to the high beams or low beams. They are one and the same from the headlight switch, and only separate after the floor dimmer to their respective places.

Another place you can use jumpers as a way of testing is the floor dimmer. Disconnect it, find out if the input wire has 12v from the headlight switch, then jumper with a small bit of wire from there to either one of the other contacts. Check your headlights.

If you jumper it to the high-beam side you can also check the high-beam indicator at that time. Making the high-beams a good first test so you can see what's going on.
With a volt-meter check the battery to get a base reading. Let's say it's 12.4v at the battery. Then check the input wire at the dimmer to make sure it's also got 12.4 or very close to it.

Good luck

Paul

 

[Jfryjfry]

Arcing and smoke indicate a short, not merely a bad ground. A bad ground *might* arc but I’d be surprised in that circuit and I certainly wouldn’t expect smoke.

I suspect you might have two issues. The ground you added from the dash might have fixed the ground issue (if there was one) and the switch might be bad causing the other. Just my remote, best guess diagnosis

 

[377]

Paul
I’m glad you said something about jumpers I was thinking about those yesterday. I didn’t get a chance to mess with it last night but I’m working on it tonight. I have used two new switches while dealing with this issue. I got a third switch last night from Steve Wisler and also got a new dimmer switch. So tonight I’m going to try to figure out what’s going on. I really appreciate all you guys’ help with this.
Paul

 

[377]

One last question you guys may have experience with. Faulty headlight switches is there a common failure point on them? Because on both the switches park lights, tail lights and courtesy lights have worked fine.

 

[DirtDonk]

There's a lot going on inside one of those switches. All separately too, so just having one area fail does not necessarily take the others with it.
And the headlights are the heavy load, so likely the first to cause trouble. But the most common "failure" more of a wearing out than failing though, is that the circuit breaker trips early and shuts the lights off temporarily until it cools down, then shuts them off again when it heats up again.
This should not happen with headlight relays though, because the load on the switch is now just a fraction of what it would have been with the headlights directly wired.
Some sort of internal resistance will build up more heat than expected, but yours is not acting like that either I don't think.

The most common failure point is actually the dimmer switch, but these days it's hard to tell because there are so many crappy parts available that it's hard to tell when you get a good one, or when the new part is the problem. That's why everybody needs to get really good at testing!

Another somewhat common failure point is the relays in these headlight kits. We've had a few go out prematurely too, and have sent new ones to the customers. Although you can also buy them new at the local parts store and keep as a spare, a failed-too-soon one is warrantied normally.

Very unusual to have both fail though, so the normal test for the relays (if high or low works, but the other does not) is to just swap the relays from one side to the other to see if the problem follows. If not, then it's not a relay. If it does, then that relay needs replacing.

Paul

 

[377]

Paul
I checked everything using a set of jumpers. Everything worked flawless using them. Turns out it was the dimmer switch. It really sucks it managed to take out two brand new headlight switches. I checked continuity on them and the headlight “circuit “ was jacked on both of them. The dimmer switch didn’t have continuity in either position. I plugged in all the new stuff and it worked fine. Thanks again to all you guys for your help. Steve, I owe you a beverage of your choice at the Lawdog Saloon for the headlight switch!
Paul