90 GMC Suburban Tailgate Problem

If you think the motor is not bad then maybe the interlock switch is bad. There is a switch mounted on the passenger side lock of the tailgate. Its purpose is to not allow the window to close unless the tailgate is completely closed. If you are handy you can change it yourself. Take the cover off the tailgate (plastic trim cover), take the steel plate cover off, reach into the tailgate and remove the passenger side lock by removing the three bolts on the side of the gate. Remove the two screws holding the switch to the latch assembly and replace with similar part. Reinstall everything and test. There is no adjustment in the side lock assembly so just be careful to remove and re-assemble the lock rod. When the switch goes bad it will allow it to go down but not up. It is an easy fix switch should cost you ~$20 and a half hour to change once you can figure how to remove the switch. A suggestion... if you can get the steel (internal) cover off reach into the tailgate and unplug the switch. Use a paper clip to short both leads on the wire and with the key crank the glass up a little (with the gate open) being sure not to bring it up too far as you don't want it to break. But by moving it up and out of the way you can get the latch out to change the switch. Post back if you need more info.

mark

This is a temp fix!!! I just changed the polarity of the pigtail that controlled the motor for the tailgate window in my 85 K5. It was enough to get it up so I didn't have to worry about it getting rain it. I'd fix it for real, but this will fix it fast. So if it sounds like it will go down, then you can "make" it go up.

~KJ~

Thanks for the posts, I tried the interlock trick and it worked perfectly. I plan on replacing it as soon as i get some more free time. i just needed a quick fix so that I could avoid the rain and other elements. Thanks a lot for the suggestions.

Dave