You need to remove the end seals, 1 screw each and the weather stripping. Put it up about 1/2 way before unbolting it from the regulator arms. That makes it easier to get at the nuts and I believe 89Bronco is right about the size of the nuts. Try soaking them with PB Blaster for a while before you attempt to unbolt them, if they are rusted stuck, they may snap the stud. It only takes about 1/2 hour max.theres 2 nuts on each side of the glass, im nit sure what size, 10mm maybe, so loosen all 4 of them and push the glass down slightly and pull the arms up to detach it, now CAREFULLY slide the glass out of the tailgate, when i did mine i pulled the trim off the end of the tailgate for more room...GOOD LUCK
Most common problem is the safety switch in the left hand latch. If that is it, most people bypass it.good news bad news!!! motor good!!! start checking wiring kinda of slow methotical work. any specific places to look for broken wires? i have juice to one side of the lead at the motor?