Headlights NOT on
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From: Tri-Cities, WA
Does the schematic show where those wires go to? If they go down to the handbrake I might start there since it was being used for about 3 weeks to bypass the DRL stuff. I have no idea, just trying NOT to have to pull all the wiring apart to get to the source of the problem.
Also was the clicking/crackling and surging of power I had earlier all part of the same problem of a possible bad ground? That would make sense to me, but so would a faulty switch.
Also was the clicking/crackling and surging of power I had earlier all part of the same problem of a possible bad ground? That would make sense to me, but so would a faulty switch.
Last edited by mySStery_machine; Aug 9, 2004 at 06:12 AM.
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From: Jacksonville, FL (originally from Toronto Canada)
No, the only headlight-related wire that goes to the parking brake is a light blue wire from the DRL module that prevents the DRLs and automatic headlights from coming on while the parking brake is engaged. The parking brake switch has only the one input wire that grounds through the switch casing when the parking brake is engaged. That means that, even if it got shorted, it wouldn't cause any damage and would only prevent automatic operation - the lights would still work using the headlight switch.
It is quite possible (even likely) that a short to ground on one of the headlight switch output wires would cause crackling or sizzling noises.
BTW, what happens when you use a jumper to connect pin J (battery power) to pin E (headlight output). Do the lights go on? Or does the jumper get hot like it's feeding a short? That might give you some indication of where the problem lies. Just be careful.
It is quite possible (even likely) that a short to ground on one of the headlight switch output wires would cause crackling or sizzling noises.
BTW, what happens when you use a jumper to connect pin J (battery power) to pin E (headlight output). Do the lights go on? Or does the jumper get hot like it's feeding a short? That might give you some indication of where the problem lies. Just be careful.
Last edited by WhiteBird00; Aug 9, 2004 at 08:07 AM.
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No lights came on but it did make a 4th of July show the first time I tried that about 2 weeks ago. This time nothing happened but the heat sink gets REALLY hot. That's about it, so it's one of those wires that's grounding out down the line? I guess I will start pulling tape later today.
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From: Jacksonville, FL (originally from Toronto Canada)
Uh, J can't be showing zero - that's the battery feed wire. Your whole car would be melting if you could read 0 ohms to ground on a hot wire.
If the wire on the E pin is showing 0 ohms to ground then that is probably the wire that is shorting out. First, unplug both headlights and then test again to see if you still have a short to ground on that wire. If so, you will need to trace it to where it's shorting. Most likely places are where the wire goes through the dash and any other place where it might have rubbed against some metal that wore through the insulation.
If the wire on the E pin is showing 0 ohms to ground then that is probably the wire that is shorting out. First, unplug both headlights and then test again to see if you still have a short to ground on that wire. If so, you will need to trace it to where it's shorting. Most likely places are where the wire goes through the dash and any other place where it might have rubbed against some metal that wore through the insulation.
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Well I went ahead and disconnected the lights and got a ohm rating of about 178 from both E and G but still nada out of J. I'm really confused and think it may be a Chevy repair day if the new headlight switch burns out once I put it in. Any more input? The ohms dropped a bit after hooking up the brights (I think, it's been so long) but still well over the 0.0, I do believe it spiked at one time to the 330 range. 
Joined: Nov 2003
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From: Jacksonville, FL (originally from Toronto Canada)
Try unplugging the wires from the switch as well as from the headlights and then check the resistance. There should be infinite resistance on the yellow wire unless there is a short in it someplace.
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Verdad Gallardo Joined: Nov 2003
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From: Jacksonville, FL (originally from Toronto Canada)
Well, you should probably do the same thing with the red wire on pin G - disconnect it from the switch and also from the DRL module and then check to make sure that there is infinite resistance to ground. If both wires check out OK then you know there isn't a short in them.
It's still possible that the DRL module itself is bad so you might want to leave it disconnected when you first plug in the new switch. If that works but they quit when you plug in the DRL module then you'll know that it is the culprit.
It's still possible that the DRL module itself is bad so you might want to leave it disconnected when you first plug in the new switch. If that works but they quit when you plug in the DRL module then you'll know that it is the culprit.
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I actually just disconnected the lights from the actual light and left the DRL module intact to get that reading on the yellow wire on pin E. I really don't want to take that risk and smoke another switch either if it is the DRL and that would happen if it worked w/out and then when I plugged in the DRL module after correct?
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From: Jacksonville, FL (originally from Toronto Canada)
Sorry, somehow I didn't get an email saying there were new postings.
Your're right about the DRL module - if it was the original problem then plugging it in could fry another switch. But what other choice do you have besides getting another module?
If you plug the headlights in and disconnect the wiring plug from the back of the headlight switch, then jumper the red 12V wire to the yellow headlight wire do the lights come on? If so, you are guaranteed to have lights after putting in a new switch. But it still leaves the possibility of the DRL module being the problem that fried the switch in the first place. Maybe you could find a cheap DRL module at a junk yard and just replace it to be safe. Unfortunately, it is solid state and the manual says there is no way to test it other than swapping it out.
Your're right about the DRL module - if it was the original problem then plugging it in could fry another switch. But what other choice do you have besides getting another module?
If you plug the headlights in and disconnect the wiring plug from the back of the headlight switch, then jumper the red 12V wire to the yellow headlight wire do the lights come on? If so, you are guaranteed to have lights after putting in a new switch. But it still leaves the possibility of the DRL module being the problem that fried the switch in the first place. Maybe you could find a cheap DRL module at a junk yard and just replace it to be safe. Unfortunately, it is solid state and the manual says there is no way to test it other than swapping it out.
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I have the cheapy DRL mod in there right now and tried the jumper WITH the switch still intact (from the rear) and nothing. Last time I tried the jumper trick it was the 4th o' Julycelebration BUT with the old DRL module. I guess tonight will be jumper w/out swtch and see if it lives. Will that be about right? Thanks!
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From: Jacksonville, FL (originally from Toronto Canada)
There are two DRL mods - disable DRLs and disable auto-headlights. Which did you do?
Try the jumper trick first with the both the headlight switch and the DRL module unplugged. If you get lights then try the new headlight switch but leave the DRL module unplugged - the lights should work. Then you've got to decide if you want to risk plugging in the DRL module and trying again. If you leave it unplugged you won't have turn signals.
You can eliminate the DRL module from operating the headlights or parking lights (and eliminate the possibility of it shorting out the lights) but still leave it functional for everything else. Just disconnect and tape up the red wire from pin D and the yellow from pin F at the DRL module black connector.
Try the jumper trick first with the both the headlight switch and the DRL module unplugged. If you get lights then try the new headlight switch but leave the DRL module unplugged - the lights should work. Then you've got to decide if you want to risk plugging in the DRL module and trying again. If you leave it unplugged you won't have turn signals.
You can eliminate the DRL module from operating the headlights or parking lights (and eliminate the possibility of it shorting out the lights) but still leave it functional for everything else. Just disconnect and tape up the red wire from pin D and the yellow from pin F at the DRL module black connector.
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I meant DRL mod as in module not as in 4 light mod sorry. But hey I got home helped my kid with some quick 4th grade stuff and went outside to try the jumper directly at the source. The outcome...HEADLIGHTS!!!!!! I guess the bad DRL module burned up the original switch somehow and then fried the secondary as well, tomorrow I'm picking up a new one and getting the front right tire replaced and getting my *** to the track!!!!!!! 
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Question for WhiteBird00.
I have a 98 TA, and looking at the wiring diagram, do the low beam lights go off when the high beam lights are on?
This is from looking at the Headlamp Dimmer Switch C(low beams), A(high beams), and B being feed by C1-F on DRL or E on Headlamp Switch.
I have a 98 TA, and looking at the wiring diagram, do the low beam lights go off when the high beam lights are on?
This is from looking at the Headlamp Dimmer Switch C(low beams), A(high beams), and B being feed by C1-F on DRL or E on Headlamp Switch.