I have a 2005 f150 super crew with the factory hitch and trailer hookup.
I have tried two trailers and both have the same problem when i plug them in.
All i can get is right brake, light right flasher, right blinker, and the brakes work.
I have no running lights and nothing at the left light. One trailer is a 28 ft
enclosed and the other is a camper i just bought. My buddy pulls the enclosed with a 2006 f250 and a 2009 f350 with no problems. Could my wires be wrong on my truck from the factory? Someone please help me. I
would like to go camping this weekend with some lights. THANKS IN ADVANCE

HUGH

 

Make sure there is no build up in the plug, then check all trailer related fuses and relays if you havn't already. Do you know if you your flat 4 works right?

 

Did you check the fuses ?

Also as FX41 posted, check for power and ground at the plug head ( both 4 and 7 pins ).

 

I have not tried the 4 way yet. Where are the fuses for the trailer harnes?

 

The fuses are listed in your owners manual, starting on page 225.

https://www.fleet.ford.com/maintenan...ls/default.asp

 

Thank you for the info. When i get home i will check them out.

P.S. Is there a way to check relays?

 

2 ways to check the circuit as a whole.

1. Jumper the Normally open contacts in the relay socket.



Next is to apply power and ground to the coil, and check the resistance on the Normally open pairs. The resistance should be < 10 ohms
Ford full ISO relay,
- the coil is on 85 & 86
- Resistance check on pins 30 & 87

Ford 1/2 ISO relay
- the coil is on pins 1 & 2.
- Resistance check on pins 3 & 5

You can also check the resistance on the coil, which should read 50 to 100 ohms.

 

Thanks alot guys. Your info was spot on. Two bad fuses. I feel stupid for not checking that first but i just didn't think of it. Thanks hugh