2007 F150 - No running lights when pulling trailer

[mi67stang]

Anyone have any idea why I would have no runnning lights, when pulling my trailer. Brake Lights work Fine, as do Turn Signals. Problem is not with trailer as running lights worked when hooked up to different vehicle.
Not sure if it is related, but the illumination light behind the compass/trip counter does not work either. Compass, trip gauge and low fuel indicator all still work, just no light!
Vehicle is equipped with Trailer Tow Pkg.
Hopefully it is just a fuse or relay.
Thanks in advance for any replies!

[kozal01]

Youve got a ground or connection issue somewhere. what plug are you using the 4 pin or the round seven pin plug? Do the lights work once the trailer lights are unplugged from the truck?

[mi67stang]

Youve got a ground or connection issue somewhere. what plug are you using the 4 pin or the round seven pin plug? Do the lights work once the trailer lights are unplugged from the truck?

Thanks kozal01 for the reply!
I use the round seven pin plug. And no, the compass/trip odom. light does not work even when not hooked to the trailer. I never thought to try the 4 pin plug. I would need to use an adapter, but may try that.
I also plan on going thru the fuses again tomorrow, and hopefully will find a blown fuse.

[Bothe]

I bet it's a fuse. I had the same problem with my old truck's LED tailgate bar. The running lights would never come on, but i went in and found a blown fuse, replaced it and it started working after that.