Throw do I replace the tailgate glass window sash on 1991gmc jimmy

Those are called sash clips, you gotta pull the inner door panel with a phillips screwdriver (power drill/driver/impact better) then pull the motor/regulator (after disconnecting your battery neg cable) and if memory serves at least one window track. (all 10mm headed bolts) Then the thing most people might miss, the little frame where the rear viewer mirror is mounted has to be loosened or removed. Once all that is done it lifts out at an angle. Many auto parts stores carry those sash clips in a "HELP!" package of generic parts. They give you two pairs for about $12, one pair is the right one. You have to get a special adhesive for remounting....

tailgate window on a 1979 GMC Jimmy will not go up or down

Door Glass REMOVAL & INSTALLATION

1. Remove the door trim panel and the inner panel water deflector.
2. Raise or lower the window, as applicable, to the half-up position. CAUTION
   Make sure to properly support the window. If the window drops into the door personal injury or window damage may result.
   
3. Support the window in the position needed to access the rivets by inserting rubber wedge door stops at the front and rear of the window between the window and inner door panel. Fig. 1: Support the window with rubber wedges in the door channel
   
   
4. Use a 1⁄4 in. (6mm) bit to drill out the attaching rivets on the sash channel. Fig. 2: Location of the window retaining rivets
   
   
5. Carefully raise the glass to remove from the sash channel, then remove the glass from the door.
6. Inspect the bushings, retainers, up stop, pins and wedges on the window for damage.
7. If necessary, remove the bushings and retainers using a prytool covered with cloth body tape.
8. If necessary, remove the following:
   1. Window front up stop bolt/screw.
   2. Up stop, nut and washer.
   3. Window stabilizer bolts/screws.
   4. Stabilizer pins, nuts and wedges. Fig. 3: Exploded view of the window glass and related components
      To install:
      
9. If removed, install the window wedges and stabilizer pins.
10. If removed, install the stabilizer pin bolts/screws and tighten to 62 inch lbs. (7 Nm).
11. Install the stabilizer pin nut, if removed and tighten to 71 inch lbs. (8 Nm).
12. If removed, install the up stop and washer.
13. If removed, install the up stop bolt/screw and nut. Tighten the bolt/screw to 62 inch lbs. (7 Nm) and the nut to 71 inch lbs. (8 Nm).
14. If removed, install the bushings and retainers.
15. Carefully position the window into the door so the holes in the bushings lines up with the holes in the channel.
16. Install the rivets in sequence.
17. If necessary, adjust the window as outlined later in this section.
18. Install the water deflector and trim panel.
19. Remove the drilled out rivets and shavings from the door.
20. Check the rivet bushings and retainers on the glass for damage. If necessary, remove the bushings using a flat-bladed tool covered with a cloth body tape. Install by snapping the rivet retainer into the bushing.
21. Lower the glass into the door and position on the sash channel so the holes in the sash line up with the holes in the bushings and retainers.
22. Using rivet tool J–29022 or equivalent, install 1⁄4 in. (6mm) peel type rivet (part No. 20184399 or equivalent) to retain the glass to sash channel.
23. Install the rear guide channel.
24. Install the front up stop to support on the inner panel.
25. Before installing the trim parts, check the window operation for performance and fit to roof rail weatherstrip.
26. Install the inner panel water deflector and the door trim panel.

Have had a few of these broncos, the rear window motor burns out on those pretty frequently. Check to see if you have power to the motor before replacing it but if your fuse is good and its not working then pretty sure it is the motor. There isn't a way to manually crank the window up but you can open the tailgate up to get to the internal components and disconnect the regulator from the glass then you can manually put the glass up and use a wedge of wood to hold the glass up. The proper fix is to replace the window motor.

your off a little on the track or you just need some silicone spray in the window grove to slide easily

The forward track channel has either rusted out, broken, or the sash clips to help keep the window level broke. We have seen all the above, but most likely is the sash clips that glue onto the lower window broke. The door panel will have to be removed, the old clips, heated with a HOT heat gun and removed, and new ones installed. Pretty easy fix with the right equip.

GM Full-Size Trucks 1980-1987 Repair Guide

REMOVAL & INSTALLATION(see Figures 1 and 2)

Non-Stationary Door Glass

1. Lower the door glass completely.
2. Remove the trim panel from the door.
3. Remove the ventilator assembly as previously outlined.
4. Slide the glass forward until the front roller is in line with the notch in the sash channel.
5. Push window forward and tilt the front portion of window up until rear roller is disengaged.
6. Put window assembly in normal position (level) and raise straight up and out.
7. Installation is the reverse of removal.

Fig. 1: Door window and regulator




Fig. 2: Removing the door glass

Manual Door Window Regulator
(see Figure 3)

1. Raise the glass to the full up position and tape it to the door frame with fabric tape.
2. Remove the door trim panel.
3. Remove the regulator to door panel attaching bolts.
4. Slide the regulator assembly rearward, disengaging the rollers from the sash panel.

A notch is provided in the sash panel to allow disengagement of the forward roller on the window regulator.

1. Collapse and remove the regulator assembly through the access hole in the door.

To install:

1. Prior to installation, lubricate the motor drive gear and regulator sector teeth.
2. Collapse the regulator and insert it through the access hole in the door.
3. Unfold the regulator and engage the forward roller to the sash cannel at sash channel notch.
4. Slide the regulator rearward to engage the rear roller to the sash channel. Also engage the lower roller to the regulator rail.
5. Slide the regulator into its proper position, and insert the regulator drive through the door panel.
6. Attach the regulator to the door.
7. Install the door trim panel.

Fig. 3: Manual window regulator

Power Window Regulator and Motor
(see Figure 4)



Fig. 4: Power window regulator and motor

1. Raise the glass to the full up position and tape it to the door frame with fabric tape.
2. Disconnect the negative battery cable.
3. Remove the door trim panel.
4. Remove the remote control bolts and lay the control aside for access.
5. Remove the regulator to door panel attaching bolts.
6. Disconnect the harness from the regulator.
7. Slide the regulator assembly rearward, disengaging the rollers from the sash panel.

A notch is provided in the sash panel to allow disengagement of the forward roller on the window regulator.

1. Remove the regulator assembly through the access hole in the door.

CAUTION Step 9 must be performed when the regulator is removed from the door. The regulator lift arms are under tension from the counterbalance spring and can cause serious injury if the motor is removed without locking the sector gear in position.

1. Drill a hole through the regulator sector gear and back plate. DO NOT drill a hole closer than 1 /2 inch; to the edge of the sector gear or back plate. Install a pan head sheet metal tapping screw (No. 10-12× 3 /4 inch;) in the drilled hole to lock the sector gear in position.
2. Remove the motor to regulator attaching screws and remove the motor from the regulator.

To install:

1. Prior to installation, lubricate the motor drive gear and regulator sector teeth.
2. Install the motor to the regulator. Make sure the motor and sector gear teeth mesh properly before installing the retaining screws.
3. Remove the screw locking the sector gear in the fixed position.
4. Reposition the motor in the door and install the wiring connector.
5. Attach the regulator to the door.

I really hope help you with this (remember rated this help) Good luck.

what happens with these grand amsare that the windows have whats called a sash glued to the bottom side of the window, and bolts to the regulator. it has one for each track of the regulator. one of them has broke or the glue came loose. the window must be removed, and id the sash is broke you can buy a replacement from the dealership. and urethane it on. run a tape line on the glue edges as a guide then remove old glue glass prime and urethane back on. sashes are not expensive I've replaced many

There is a small plunger on the tailgate, see if that is still doing it's job to push the glass out abit. the other thing too is if the two pistons that hold the glass up is weak can do that and if the car has been out in the sun for a while, i find that the weather strip hold the glass down. Good luck and let me know how your did. 

Followed owners manual for emergency opening of rear window glass.
Removed upholstery panel from the tailgate once glass was opened. Found a broke (plastic) actuator arm on the actuating motor.
Ordered new one for replacement.