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I replaced the wiring harness in my Cutlass and along with it, the ignition and light switch. The switches were getting sloppy and sticky. The wiring and ignition switch are performing correctly, but the light switch has let me down. Twice! The first switch was ~$13 from Amazon. I figured they're all made in China so it doesn't make a difference, right. It doesn't turn on the headlights. Confirmed with a vom, no continuity to the headlight circuit. Switch 2, I ponied up for the "Genuine GM" part. $35 , all 8 terminals, front parking lights turn off when the headlights are turned on, and everything. Still made in China, but for some unknown reason, I expected better quality. Nope! Same thing, no power to the headlight circuit. Sent that one back! Unfortunately I think I already tossed the original or it would be back in there. Anybody recently bought a light switch for a 67 that actually works?
Make sure the shaft is seating correctly and the **** is not sticking out too far. Alternatively, the high beam switch is between the light switch and the lights themselves.
Make sure the shaft is seating correctly and the **** is not sticking out too far. Alternatively, the high beam switch is between the light switch and the lights themselves.
I assume that when the OP says "no power to the headlight circuit", he's talking about the blue wire between the headlight switch and the dimmer switch.
Correct Joe. There is no power/connectivity between the main power input terminal and the headlight output terminal of the switch. I have replaced the dimmer switch along with all the other switches because it was also sloppy and sticky. I did not realize there was a circuit breaker inside the switch so I will check that tonight. The parking lights work though so can I assume it interupts the headlight output only? And how do I reset it?
If the breaker is resetting on 2 separate, new switches, that would indicate a load that is too high or a dead short.
Unplug the headlights, and see if it works (power out). If so, it's the, or a, bulb(s). If still no power, there's a short.
Last edited by fleming442; December 4th, 2023 at 08:24 AM.
If the breaker is resetting on 2 separate, new switches, that would indicate a load that is too high or a dead short.
Correct, but if the connector at the dimmer is unplugged and there is still no power on the blue wire, then either there is a hard short to ground somewhere in that blue wire or the breaker in the switch is bad. Verify that there isn't a problem at the connector to the switch. Unplug both the dimmer and the headlight switch and see if there is continuity from the blue wire to ground.
Thanks Guys! They are new LED headlights and they worked before, so I will see if there are any problems with the wiring. There shouldn't because I kept the factory wiring for the lights under the hood. It was still in very good condition. Sideways points of view always help with diagnostics. I'll let you know what I find.
Thanks Guys! They are new LED headlights and they worked before, so I will see if there are any problems with the wiring. There shouldn't because I kept the factory wiring for the lights under the hood. It was still in very good condition. Sideways points of view always help with diagnostics. I'll let you know what I find.
You really need to bench test those lights first. Figure out which is power and ground, then use a battery to make sure they're wired correctly. The H4 and sealed beam plugs are the same, but pinned differently, I believe. They could be on the H4 pinout, wired backwards polarity, or just defective, because....... China.
Last edited by fleming442; December 4th, 2023 at 10:35 AM.
You really need to bench test those lights first. Figure out which is power and ground, then use a battery to make sure they're wired correctly. The H4 and sealed beam plugs are the same, but pinned differently, I believe. They could be on the H4 pinout, wired backwards polarity, or just defective, because....... China.
Again, if there isn't power on the blue wire from the switch to the dimmer, the headlights are irrelevant. Don't make work.
Again, if there isn't power on the blue wire from the switch to the dimmer, the headlights are irrelevant. Don't make work.
Understood, but you of all people should be the first to discount the quality of a non-OEM part. I've had LEDs wired backwards right out of the box, and LEDs don't work backwards.
Understood, but you of all people should be the first to discount the quality of a non-OEM part. I've had LEDs wired backwards right out of the box, and LEDs don't work backwards.
From Post #9:
Originally Posted by cjsdad
They are new LED headlights and they worked before,
So the lights were working with the old headlight switch, and the only thing that has changed is the switch.
If you want more fun than checking for grounded hot wires, get a cheapie inline fuse holder, load it up with whatever the equivalent fuse is, and jump around the headlight switch. Set up with battery disconnected. Connect battery; you'll either blow fuse (short), lights will work, or they won't.
Please bench test the switches with ohm meter (on your work bench, not in the car), also check the case of the switch. I bet the case is grounded when you turn the headlights on and the breaker goes.
LOL! Lots of fun stuff related to a simple light switch. Since the switch has no conductivity to the headlight circuit after it is unplugged, I'm guessing the internal circuit breaker is now bad and won't reset. I will probably end up with a fuse holder wired in-line if possible. That being said, the lights did work with the original light switch and dimmer switch, highs n lows. All I did to the wiring for the front lights was re-wrap them with cloth wiring tape, but something has gone wrong. Knowing that there is a breaker in the switch gives me a starting point that I didn't have before. Like I said, I'll let you know what I find.
Originally Posted by Koda
Please bench test the switches with ohm meter (on your work bench, not in the car),
Did that... Said so in my first post.
Originally Posted by Koda
also check the case of the switch. I bet the case is grounded when you turn the headlights on and the breaker goes.
Can you give me a little bit more on that? How will the case become grounded with the switch turned on? Through the headlight wire if it is touching ground? Once it is installed, the case of the switch would become grounded through the grounding straps on the back of the dash anyway, right? If the case can become grounded through the headlight wire, wouldn't that mean it can become energized by that same headlight wire? And would therefore blow a fuse or trip the breaker as soon as the switch was turned on? You got some 'splaining to do Lucy!
Last edited by cjsdad; December 4th, 2023 at 01:21 PM.
The case of the switch is grounded upon installation and the only purpose of that ground is to complete the courtesy light circuit. What happens if you jumper the plug with a paper clip?
The case of the switch is grounded upon installation and the only purpose of that ground is to complete the courtesy light circuit. What happens if you jumper the plug with a paper clip?
Just in case, I would make that a FUSED "paper clip"...
Figured it out, my worthless assistant plugged the main power lead back into the wrong spot after I cleaned the connector! The lights work correctly now.
And just to satisfy curiosities, the headlights are plug-n-play.
Can you give me a little bit more on that? How will the case become grounded with the switch turned on? Through the headlight wire if it is touching ground? Once it is installed, the case of the switch would become grounded through the grounding straps on the back of the dash anyway, right? If the case can become grounded through the headlight wire, wouldn't that mean it can become energized by that same headlight wire? And would therefore blow a fuse or trip the breaker as soon as the switch was turned on? You got some 'splaining to do Lucy!
I'm glad you have it figured out. What I meant was that the hot side could be shorted to ground at the terminal out to the headlights. It would only be tripping when the switch is to headlights as the short is behind the switch in this example.
However, since you've got it, we can instead talk about I Love Lucy. The phrase "you've got some 'splaining to do, Lucy!" was used on occasion by Desi Arnaz towards Lucy when she had made a mess of things and he was demanding to know why. It shouldn't be used when someone is trying to help you and you don't understand the information.
I'm glad you have it figured out. What I meant was that the hot side could be shorted to ground at the terminal out to the headlights. It would only be tripping when the switch is to headlights as the short is behind the switch in this example.
However, since you've got it, we can instead talk about I Love Lucy. The phrase "you've got some 'splaining to do, Lucy!" was used on occasion by Desi Arnaz towards Lucy when she had made a mess of things and he was demanding to know why. It shouldn't be used when someone is trying to help you and you don't understand the information.
Even if the headlight circuit were shorted to ground, the switch casing would not have been "hot". That circuit doesn't make contact with the case. Now if the dash light circuit became shorted, it would.
Even if the headlight circuit were shorted to ground, the switch casing would not have been "hot". That circuit doesn't make contact with the case. Now if the dash light circuit became shorted, it would.
Yeah, because we all knew the connector was repinned
Reminds me of an old thread on a quadrajet flooding no matter what he tried. Come to find out he had an electric fuel pump, not mentioned, no regulator not mentioned and 20 psi...hmmm more info is always good.....
December 3rd, 2023, 04:42 PM
