Symptoms
The rear glass won't go up or down from the key switch or the dash switch, the motor runs but the glass doesn't move, or the motor gets hot and stops.
The fix, step by step
- First make sure the tailgate is fully latched.
- Wikipedia notes that a safety switch stops the glass rising if it isn't.
- Check for power at the motor from both the key switch and the dash switch.
- If the motor spins but the glass doesn't move, the cable between the motor and the regulator (similar to a speedometer cable) has probably failed.
- If the motor doesn't run, or overheats, replace it.
- Remove the inner tailgate panel, support the heavy glass, and replace the cable, motor or regulator.
- Lubricate the tracks before you refit the panel.
Tools & part numbers
- Trim tools
- test light or multimeter
- socket set
- white lithium grease
- a helper to hold the glass
Where to buy the parts
73–91 Suburban tailgate parts (search)Auto Metal Direct ↗
1985 Suburban body and electrical partsRockAuto ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Chevrolet/GMC Suburban (1973–1991 square body) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.