i have one fog light that works and one that doesn't.....the bulb in the one that doesn't work is good.........i am getting about 5v at the fog light that doesn't work.......tried 3 different fog light switches.......

anyone have an idea?

 

Sounds like the relay for the fogs, if there is one, voltage drop is to much somewhere, maybe between the switch and the lights theres a bad ground, which wouldnt make sence because you still got 5v at the light which means the circuit is still complete. which means theres a relay somewhere thats messed up and not sending the correct voltage to one, did you check the voltage at the one that works?, and i know a kid that had to high of wattage bulb in his fogs and one burnt the harness....Somethin to think about

 

If it were a relay issue, then both lamps would be affected. Sounds more like a ground issue.

How do you know the non-working lamp bulb is good?

 

the fillament is still complete....the relay is good....i swapped it with another relay also....

 

ground wires...

 

Definately grounding itself out somewhere

 

check those ground wires

 

even though the filament looks good, it mite be bad. that happened in my headlight

 

Are you using the ground wire in the lamp connector to check your voltage? Try using the chassis somewhere for ground when reading the power. If it's still only 5v, you have a bad power wire to THAT foglamp socket. If it goes to 12v, then you have a bad ground for that foglamp.

It wouldn't be the first time we've heard of foglamp wiring problems, given the location and amount of heat they generate. I'd immediately suspect a problem with the lamp connector, corrosion being most likely.

 

i am checking the voltage by using the frame as a grounding point.....i am using the socket plug for the + side of the tester......

 

I'd check the wires myself. I had that happen to me once. I replaced all the wires and it worked........

 

2 things I'd try... take the bulb and attach 2 wires to its pins. Then connect it directly to the battery and see if it still lights the same, or at full brightness.

If it does light up fully, then take a voltage reading from behind the foglight plug. You can do this by taking push pins or sewing pins and pushing them into the wires, then connecting your voltmeter to the pins. If your voltage remains at 5v, you know there's a problem somewhere in the wiring. If it is around 12v, then you know your plug for the bulb is bad.

 

got it fixed.....well actually it fixed itself.......got in the truck yesterday and wala they both worked fine...