This is very strange, all of a sudden the tail and brake lights stopped working also the turn signals are doing the fast blinking thing. I have checked every fuse in the truck from under the dash to under the hood, I have looked at all the wiring under the body and the trailer wiring. The turn signals are very dim in the rear and the emergency flashers do work but are also very dim. I did notice that one time when I turned the lightrs on the right rear tail light came on very dim but as soon as I turned on the ignition the tail light went out. Has anyone had a similar condition ? could it be a problem with a multi switch? ANY help would be greatly appreciated. Thank You, Bill

 

Bump. At first I thought it was maybe just a few bulbs. Its not uncommon for them both to blow at the same time, but with the dimming of the lights, it sounds like a wiring issue.. Have you tried to swap the bulbs with new?

 

Hi, yes I switched the bulbs first with each other and then with new ones, and got the same results.

 

Are these your truck lights that are dim, or your trailer lights? If it is the trailer, I would suspect a bad ground.

 

Even if it's the truck lights, check your grounds.

They're just as important as the hot leads to make the bulbs light up.

And easily forgotten.....

Pop

 

I can't remember the details but we had a 2003 7.3 F450 with an aftermarket bed and every so often we would lose the tail lights. Come to find out there is some relay mounted above or near the steering column that would go bad. Replace the relay and everything went back to working. Thats not to say there was not a ground problem on the bed that we could not find, but the relay fixed it for awhile.

Good luck.

 

I would be suspectecting the multifuntion switch. I have seen them do some weird things.