Im stumped. I have a 2007 f150 lariat 4x4, Yesterday while trying to figure out why my plug for my trailer didnt have power to the tail light lug i was trying to find the wire going to my tail lights on my truck with one of those test lights that stick the wire. Well i found it and at the same time i poked the bed of the truck which in turn shorted out the tail lights on the truck that were working fine. Well naturally i figured i blew a fuse. I checked all the fuses and none were blown. I decided to go ahead and put new ones in for the tail lights anyways but still nothing. I pulled all the fuses in the box twice to check them but they were all good. I checked uner the hood and found the little box that has the relays and a 5 amp fuse. Checked it and it was good also. Everything else on the truck works including all lights except for the parking lights on the front and the tail lights and license plate lights, which im sure they all all tied in. I spent most of the day trying to track down the problem. I am totally stumped. Any ideas? Could it be one of the relays or one of the funny looking 30 amp fuses in the fuse box? The book doesnt really give me much info as far as fuse location, I called the dealer and they said it the tail light fuse was either # 10 or #42. They were good but like stated before. Changed them anyways. Still no tail lights on truck.I am at a total loss now. Thanks in advance for any help.

Steve

 

How are you checking the fuses ( a meter or pull and stare at it ) ?

Not too sure why you were testing the truck's parking lamps if you were having issues with the trailer, those are 2 different fuses.

Manual lists the parking lamps as Fuse #6 ( page 276 ), this is the one you want to test with a meter on both sides of the pins on the back of the fuse while installed in the fuse panel.

The truck's parking lamps are not controlled by a relay, only the trailer tow adapter parking lamps is ( which the parking lamps on the truck is powering the coil on that relay - the parking lamps on the trailer tow adapter will be dead until the truck's parking lamps work again ).

Are you sure you shorted the parking lamp circuit to ground ( should have been a brown wire on the truck's wiring harness ) ?

 

Well low and behold. It was the number 6 fuse after all. I got me a test light and checked it and sure enough it was bad. I guess i learned my lesson to not just always eyeball the fuse.It actually looked good. Thank you so much for your help and imput.