I installed aftermarket foglights on my non foglight 2001 f-150. They were working fine until it started getting cold. When its cold outside, they wont work. I followed instructions and installed the relay, fuse and got power from the ignition wire so they only work when the truck is on, but are controlled by a switch to turn them off when i want. Im gonna put hids in them and was wondering what could be wrong, should i rewire them again and get power from somewhere else? But where? Thanx in advance.

 

You are going to have to get a testlight or meter and see where the problem is. Poke around and see where you are losing voltage in the wiring.

 

One of two things are happening, you are either loosing voltage or ground. You can start on either side, but I find the ground to be a problem more often than the power. Check to make sure you have a good ground at the lights and at the relay, a loose connection either place can kill the whole circuit. If good switch over to the power side and I tend to work backwards. Obviously, if the ground is good you don't have power to the lights, so go to the relay. Do you have fused power to the relay, if not fix it, if so, then do you have power from your switch. If you have both and your ground at the relay has already checked out to be good, your relay is bad. If you don't have power from the switch, go to the switch and see if you have power to it, and just keep working your way back to the power source from the ignition, and you should be able to find the problem. If I had to guess, since you said they quit working when it got cold, I would say it is either a loose ground, or the relay. I don't know what kind of lights you have, but most of the cheap ones have junk for wiring. I usually throw the wiring away and run my own, including a good relay and switch.

Hope this helps.

 

thanx for the info guys, Im gonna check that out this weekend.

 

Thanx guys, I checked all the wiring and the only problem was the power wire from the fuse box under the dash where i got power from, it was lose. Installed the hids and works perfect.

 

Glad to hear you found the problem.
TC