mustang - I sure wish you were close too!
I am including some pictures this time.
As per the instructions on the Prodigy controller he wired the blue brake line into the 7 way plug on the tow vehicle. He would be all set to just plug this into the trailer but for the original problem - the GMC uses a separate line for the brake (stop) light and the AS does not.
If we add the converter as suggested the tow vehicle side is a 5 flat plug which means brake, r turn, l turn, running, and ground so what do you do with the brake blue line??
Right now he has the AS wired as follows:
Do they make a 6 flat converter?