Yo Bngeejmpr,
As Skitter advised.
If same issue;
Inspect weatherstrip for grime, lack of lubrication. Clean ws with water/Dawn mixture, then clean water.
Ford recommends, "Use Silicone Lubricant C0AZ-19553-AA (jelly) or D7AZ-19553-AA (spray) or equivalent meeting Ford specification ESR-M13P4-A on the door and window weatherstrips whenever necessary.
Silicone lubricant helps avoid weatherstrip squeaks and retards excess weatherstrip wear from chafing between the glass and the weatherstrip. It also helps to retain glass alignment by reducing friction between the glass frame and the rubber weatherstrip.
miesk5 note, test the silicone on a regular styrofoam cup first; if the cup gets funky or melts, then the can or tube contans oil, a regular occurrence now, esp if from China.
More tg **** info:
Use Multi-Purpose Grease or equivalent meeting Ford specifications ESR-M1C159-A and ESB-M1C106-B to lubricate door and tailgate hinges. Apply an even coat to all hinge pivot points as outlined in the maintenance schedules or when a binding or squeaking condition occurs..." I bought a can of Motorcraft
Multi-Purpose Grease @ Advance Auto
I use DuPont™ Non-Stick Dry Film Lubricant with Teflon™ on the flocked edges that hug the glass. See attached pic
"Take off the TG access cover and spray Tri-Flow in the tracks on either side so the regulator toggles slide up and down easy" by our late friend here JKossarides.
"The best grease for the slides & tracks is PTFE". by Steve
Is window regulator rusted badly? If so, clean & **** it with multi purpose grease.
Are Glass rollers ok? They may need to be replaced.
Ensure that the motor is mounted properly to the back of the regulator.
Tailgate could be mis-aligned. Inspect gaps between each side of the tailgate and the quarter panels. If the tailgate is too high or low, the latch jaws will cut into the striker bushings, so inspect them.
Tailgate Motor Rebuild wirh Dorman Roller kit and Regulator Removal with pics in a 92 @
https://www.fullsizebronco.com/threads/fixing-the-rear-window-motor.179496/
Tailgate Glass Roller Replacement @
https://www.fullsizebronco.com/threads/replacing-the-swivel-slide-and-rear-window.160291/
"...
All '80-96 t/g wiring runs from the dash switch (F2TZ-14529-A
Motorcraft SW7071 ~$25~65) out the firewall along the frame to the rear bumper up to the L taillight and into the t/g. '80-86 have a large round 3-wire connector in the LHR taillight well; those with rear defrost also have a 1-wire connector. All years with rear defrost have a ground ring screwed to the body in the taillight well. I think '87-91 have the large round connector in front of the taillight AND a smaller round 4-wire connector inside the frame at the LHR body mount. '92-96 only have the frame connector.
Normal operation is as follows:
RAISE from the dash switch:
Power flows thru fuse 14 thru the LB/BK wire thru the IP switch UP contacts thru the P/LG wire thru the key switch UP contacts thru the Y/R wire to the motor brushes, commutator, & windings; then it grounds thru the motor's internal CB, out thru the R/Y wire thru the latch switch thru the T/Bk wire thru the key switch DOWN contacts thru the Pk/LB wire thru the IP switch DOWN contacts to the Bk wire to the ground in the kick panel (or dash on older Broncos).
LOWER from the dash switch:
Power flows thru fuse 14 thru the LB/BK wire thru the IP switch DOWN contacts thru the Pk/LB wire thru the key switch DOWN contacts thru the T/Bk wire thru the latch switch thru the R/Y wire thru the motor's internal CB to the motor brushes, commutator, & windings; then it grounds out thru the Y/R wire thru the key switch UP contacts thru the P/LG wire thru the IP switch UP contacts to the Bk wire to the ground in the kick panel (or dash on older Broncos).
RAISE from the key switch:
Power flows thru fuse 12 thru the BK/Wh wire thru the key switch thru the UP contacts thru the Y/R wire to the motor brushes, commutator, & windings; then it grounds thru the motor's internal CB out thru the R/Y wire thru the latch switch thru the T/Bk wire thru the key switch DOWN contacts thru the Pk/LB wire thru the IP switch DOWN contacts to the Bk wire to the ground in the kick panel (or dash on older Broncos).
LOWER from the key switch:
Power flows thru fuse 12 thru the BK/Wh wire thru the key switch DOWN contacts thru the T/Bk wire thru the latch switch thru the R/Y wire thru the motor's internal CB to the motor brushes, commutator, & windings; then it grounds out thru the Y/R wire thru the key switch UP contacts thru the P/LG wire thru the IP switch UP contacts to the Bk wire to the ground in the kick panel (or dash on older Broncos).
Note that in ALL cases, EVERY switch is used, and the circuit ALWAYS grounds at the same point." By Steve