EMERGENCY WINDOW REGULATOR REPAIR!!!
Figures... I'm trying to diagnose *** is wrong with the brakes on the trailer (found one had a wire separated from its crimp, possibly shorting to the axle/frame and causing the controller to trip?), fixed that, all the others looked good, rolled down the windows in the jeep and POP! driver's rear goes all the way down on its own. <insert naughty words>
Pull the door apart and yep, the nylon piece shattered. Luckily I have the metal replacements waiting. Only one left is the passenger rear now.
Also, the kits I got, you have pop the stud out of the metal bracket attached to the glass, and the rears regulator bits have retainer holes that are bigger than the hole in the bracket on the window. had to drill out the hole in the window bracket, carefully.