2006 F150 with factory tow package. Have used it to pull boat and horse trailer in the past and no issues with trailer lights. Went to connect to horse trailer and there are no lights at all. Used test light with truck running lights on and flashers on and get no power at either the 7 way or way plug. Confirmed I had good ground on test light by checking it against license plate light.

Checked the connections of the harness and all connections appear to be ok. Checked the fuses for the left and right turn signals with the test light and get no power at either side of the fuses. Not sure where to go from here. Any help would be appreciated.

 

https://www.f150online.com/forums/to...locations.html

Post #20. There are several relays and fuses you need to check.