Fog lights not working, calling all electricians |
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Fog lights not working, calling all electricians |
malcolm2 |
Sep 28 2014, 02:26 PM
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#1
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Advanced Member Group: Members Posts: 2,745 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
OK, I know enough about elec. to test a few things so here is what I found once home from Okteenerfest.
Fog lights, driving lights, whatever you want to call them just quit working. The pull knob lights up I get 12v in the front trunk at the connection from the main harness. (that is with the connection separated) {with all wire connected, I get no reading} Grounds have continuity there too. I did not get 12 volts once I took the light apart, not the bulb holder, just the light was apart and I used an alligator clip to ground it. No volts. If I remove the alligator clip from the hanging light in the picture below and put the red lead of the VM on the white/ylw wire at the bulb holder THEN the black lead of the VM to a bolt on the car..... I get 12 volts. So with the bulb holder or the complete fixture assembled and grounded I get nothing. What is going wrong here? |
Mike Bellis |
Sep 28 2014, 03:07 PM
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#2
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Resident Electrician Group: Members Posts: 8,345 Joined: 22-June 09 From: Midlothian TX Member No.: 10,496 Region Association: None |
If you read 12V on the ground lead, through the lamp, with it disconnected from the car, the circuit is good. You may have a really bad ground. Run a ground lead all the way to the battery negative for testing and see if the lamp will light up.
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malcolm2 |
Sep 28 2014, 03:42 PM
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#3
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Advanced Member Group: Members Posts: 2,745 Joined: 31-May 11 From: Nashville Member No.: 13,139 Region Association: South East States |
If you read 12V on the ground lead, through the lamp, with it disconnected from the car, the circuit is good. You may have a really bad ground. Run a ground lead all the way to the battery negative for testing and see if the lamp will light up. OK, the blue wire hanging down is straight from the battery - side. With the black clip on the horn, and the red one on the bulb center, I get 12v. Car is idling and headlights are on LOW, along with the fog knob being pulled out. Then... with the black clip on the blue from -BATT I get 0. edit: not a symptom anymore |
Dave_Darling |
Sep 28 2014, 03:47 PM
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#4
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914 Idiot Group: Members Posts: 14,986 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
Strangely enough, I do NOT get continuity between the blue wire directly from - BATT to a bolt on the car or the horn... (IMG:style_emoticons/default/confused24.gif) I'd say that is a pretty big red flag there. Time to start checking all of your grounds. Remember that paint is not a good conductor, so if you're checking on painted parts you may need to wire-brush the paint away. --DD |
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