So I have a problem with something electrical on my truck as far as the tow package plug in goes but have no clue what I need to do to fix it. Every trailer I hook up to it the left side lights dont work, at first I thought maybe it was just the specific trailer I was using had bad bulbs/wiring harness but then I hooked up to 2 or 3 other trailers as well and each one of the the same problem. The right side works perfect but the left side is completely dead, no running lights, break lights, turn signals, nothing. Any clue whats wrong and what I need to do to get this fixed?

 

1. Some info on your truck ( MY Trim, cab, etc ) , or complete your profile.

2. Have you tried checking the trailer tow adapter with a meter, both the 4 pin and the 7 pin ?

 

check your fuses

i have an led bar under my tailgate that did that, thought it was the led's but it did it with my trailer too. so i took it to ford under the bumper to bumper warranty thinking it was a short. they charged me $60 some bucks for a diag and some fuses...bumper to bumper my @ss

 

Yea forgot about the details, it an 03 F150 xlt extended cab 4x4 5.4 auto with the factory tow package. Havent stuck a multimeter on it yet cause I'm away at school right now and wont be back home to use one for a couple days at the earliest. Also is there a fuse just for the left side of the towing package? I assumed there was just one for both sides which is why I havent checked the fuses.

 

There is a separate fuse for each side.
Check your owners manual, page 182.

Battery Junction Box ( under the hood )

Fuse # 19 : Trailer/Camper adapter (right stop/turn lamp)
Fuse #20 : Trailer/Camper adapter (left stop/turn lamp)