Trailer Output - Missing Right Side Output

[MotorCityJack]

Q: I think I may have faultly wiring in the vehicle for my trailer hookup.

 

Vehicle: 2007 GMC Yukon, 4x4, 5.3L V8 w/ AFM

 

Background: On boat trailer, right brake light / turn signal lamp was not functional when attached to the Yukon. Left side boat trailer lights work when hooked up to Yukon. Boat dealer tested and found trailer lights work. Using spare 12 volt battery, I confirmed trailer lights work - both left side and right side.

 

On Yukon, replaced blown 10 amp fuse for the trailer under the hood. Tested output at rear of vehicle and found no voltage. I have not previously towed a trailer with this vehicle and have no proof the wiring for it ever worked - may have been defective when it left the factory. I am the original owner of the Yukon so no other knucklehead has been playing around with the wiring. This is the only trailer I tow with this vehicle.

 

My question - is there another fuse box or some other servicable item that would allow me to get the output for right brake / turn signal at the rear of the vehicle before I spend hours and $$$ at the dealer trying to get this fixed?

 

Thanks for taking the time to read my post. Hopefully I have given you enough detail to assist!