Rear tailgate from circa 1987 K5 Blaze in 1973 full top. Worked fine till rear gate wasnt completely latched and window jamed at top. Had to remove top to loosen Window. Unfortunately when unlocked tailgate, it fell & window which was fully open flopped hard. Didnt break. Now, 2 motors later, wont go up or down more than 6 inches unless use portable drill on cable. Then works. I need diagram of regulator to rebuild it. Probably bent. Have new regulator, motor etc comming in case old one too badly damaged. But....need to know how to replace it and schematic or diagram.

 

its been a while since i replaced one but pretty sure it was really simple. just take off the access panel on the tailgate the regulator is attached the motor with a cable, kinda like a speedometer cable, just unscrew that off the motor. then the regulator is held on by like 4 bolts somewhere under there and it pretty much just comes right out. you have to lower the window down to about half way to get at the rail bolts that bolts the regulator to the window rail. if the window is jammed you can still get at them but itll be a pain. 7/16s bolts.

it might be the motor is badly grounded too

 

what about the safety switch, those went bad from time to time on those tailgates

 

Thanks, The safety switch is ok, wouldnt move at all if wasnt. I can move the window using a drill, but what I dont under stand is why, with the drill motor I can raise and lower the window at will. I have installed 3 different motors, finally got a new one that would at least raise and lower it about 4 inches. I even disconected the wiring plug and put direct power from the battery to the motor and that didnt make any difference. Only thougth is the there is too much resistance moving the glass and the motor doesnt have enough power?? Used to work fine tho. I'm open for suggestions. Thanks for your help.

 

did you try bypassing the main switch to change between up and down, to see if the switch is starting to fail?

 

i've had a slow rear window in my current 'Burb pretty much since i got it.

other than buying a GM motor (they seem to be the strongerst), have you tried lubing the cam gears for the lift arms? i know i was getting alot of drag before doing that.

just noticed that your truck has cables.........don't think i've seen that on them before.

anyone know when they switched the mechanisim in the gates?

 

mines an 82 and its powered, i know it was one of the early ones so early 80s

 

i wonder if your motor isnt being grounded properly. the motor itself grounds to the tailgate. try running a long thick wire from the negative on your battery to the motor and see if that fixes it

 

Thanks all...but - 3 motors all work fine. 2 regulators, installed and greased and lubed and pretested. All work fine. Problem.....when the tailgate is down & latch closed on tailgate so window will work, the motor pushes the window aout (effectively up) just fine but wont retract it. With tailgate in place, the motors will retract (down) the window but will not push it up more then 4 inches. Too much resistance. However, for 3 years everything worked fine. I've been thru 2 rebuilt and currently a new motor. When I use a drill on the cable, it moves the window up and down fine. I've bypassed the switch and pulled power directly from the batter to the motor with the same results ??????? HELP HELP HELP I'm ready to change back to a wind up.
dud

 

Not that familiar with full size Blazers but... Do you have any sort of tracks or guides that might have been tweaked when the window slammed down? It might have been getting that way anyway from ewading you original post. Sounds like something is jamming it or making it skewed. The window circuit has an auto restting circuit breaker in it (most likely) and you're probably loading it up to where it pops which is why your drill works on it. Happens though. I had a side window that did the same thing and it was a worn and screwed up track. Don't know if you have clips (plastic guides) in the sides of the window but if you do they can vause a real headache. Just a few thoughts on the subject. It sounds like your problem is mechanical not electrical.