Need some help please! Got a new-to-me 2011 Ford F-150 and when I hook up horse trailer I get running lights, no brake or signal lights. I cleaned out the hookup real good, and changed the fuses. Still nothing. I am at a loss.

 

With a simple test light you can verify if power is coming out of the plug on the vehicle.when signal lights are turned on.
If power is available there , check other end of cable for power coming out of it .
Let us know what you get?

 

Thank you for your response!!
Trailer guy put a "tester" of sorts (not sure what you call it) on the plugin at the tailgate of my truck today. Said there is nothing there on 2 pins? I'm not sure what that means. He suggested fuses, but I already changed them. He changed them anyway ( incase I did it wrong) and still nothing.

 

There are relays that send the power back to the trailer plug when a turn signal is selected.
Before we get involved with them, are the rear signal and stop lamps on the 150 working correctly?

 

Did you take the clear plastic off the light yet?
FORD built Tough.