Headlight voltage supply wire
01-31-2013, 09:53 AM
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Headlight voltage supply wire
Hi,
I have an 82 PU. My headlights don't seem to want to work. yesterday I quickly verified that the light switch was working, that the relays were working, and that everything was hooked up properly.
If I use an alligator clip to put +12V to the "Always hot" pin of the headlight relay, the headlights will function.
This wire seems to be a heavy gauge wire, Red W/ Blue stripe.
Well, I see a similar gauged wire extending from the harness and connecting to the + terminal of the battery. It looks *exactly* liek the wire going into the relay.
Except... That when I put +12 into it, the headlights still do not work.
Where is the main supply voltage for the headlights coming in from? The fuse box? Perhaps I will check that next, although the fuses are downstream from the voltage, not upstream.
I have an 82 PU. My headlights don't seem to want to work. yesterday I quickly verified that the light switch was working, that the relays were working, and that everything was hooked up properly.
If I use an alligator clip to put +12V to the "Always hot" pin of the headlight relay, the headlights will function.
This wire seems to be a heavy gauge wire, Red W/ Blue stripe.
Well, I see a similar gauged wire extending from the harness and connecting to the + terminal of the battery. It looks *exactly* liek the wire going into the relay.
Except... That when I put +12 into it, the headlights still do not work.
Where is the main supply voltage for the headlights coming in from? The fuse box? Perhaps I will check that next, although the fuses are downstream from the voltage, not upstream.
01-31-2013, 10:17 AM
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I should ask, where is the fusible link? I don't see it anywhere!
Got it, there was a break in the wire in the insulation.
Got it, there was a break in the wire in the insulation.
Last edited by thetundrawolf; 01-31-2013 at 04:37 PM.
02-08-2013, 10:27 AM
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By the way, the wire used on the headlights is called "fusible link wiring". Basically, it is built in such a way that if it takes a dead short, a section of wire will blow out. The stuff is actually kind of a PITA, it can make troubleshooting a problem quite difficult.
Voltage to the headlights will come from a 12v relay under the drivers side dash. A lot of times, these relays get stuck or fail. Locate it, and try flicking it with your fingernail or tapping it with something, then try actuating it. You have a50% chance of fixing the problem. If not, you are down to troubleshooting voltage and continuity with a multimeter. Good luck!
Voltage to the headlights will come from a 12v relay under the drivers side dash. A lot of times, these relays get stuck or fail. Locate it, and try flicking it with your fingernail or tapping it with something, then try actuating it. You have a50% chance of fixing the problem. If not, you are down to troubleshooting voltage and continuity with a multimeter. Good luck!
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