Something just didn't seem right about the brakes, specifically the trailer brakes. So I'd read and reread the manual, watched every youtube video on the subject and realized what a dummy I've been!
I've been hauling this thing around with no brakes! I was using the 4-pin to 7-pin adapter and it never dawned on me that this was ONLY good for lights! Duh! Duh! Duh! LOL
So after leaving the doctor's office I went out to the field where I parked the rig and swapped the adapter out and coiled up the 4-pin and plugged in the 7-pin. Lights all worked as before but now when I moved the slider on the brake controller, the little gain bars lit up! They didn't before.
Pulled out onto a sleepy road with no traffic and started setting the gain and got up to 7.5 and still couldn't get the brakes to lock up on the trailer. Trailer was empty too. At 7.5 and moving the slider it stopped real nice, even the truck without using the Yukon's brakes.
Darn, now I want to go out and tow again but was only a few miles away from my buddy's shop so I brought it over there and made a spectacle out of my trailer backing abilities and garnered the sympathies of the local mechanics who guided me in close enough and they picked the trailer up off the hitch and moved it into place right proper! LOL
I'm a slow learner and learn best by doing, not being told or being shown but by doing. Well, now I done it! LOL
I wanted to weigh it but we were too busy getting the house transformed into a home yesterday. Maybe next time.