How do you fix a 99 Mercury Mystique sunroof that is stuck open?

Answer 1

Your sunroof has a stipped plastic gear in the sunroof motor assembly. Access your motor by prying out your overhead light assembly. Remove the exposed screws and slide the plastic cover aft (it may be difficult to remove because the housing is "clipped" in place). A plastic cover protects the motor and gears. Simply remove the cover to access the gears. Your motor more than likely has a worm gear and your mating gear (which is plastic) has sheared it's teeth in one section or been sheared all the way around. Remove the motor and all but the crank assembly's gear. You can now manually turn the gear by hand while applying pressure on the sunroof in a forward direction. The motion will be difficult and slow, but you'll finally be able to turn the crank assembly till it reaches a "locking" detent. You'll be able to feel this as it snaps into place. Your sunroof is now locked into place. You can either purchase a new gear (around 55 dollars US) or replace the motor. Installation is as simple as reversing the steps above. The most difficult part is convincing yourself to try to fix it. I have found that these gears strip for two reasons. Number one is aging gears and number two the track usually never sees any lubricant. Your sunroof has moving "chains" (for lack of better term) in a track. After replacing the gear be sure to lube this track. (You can only gain access about two-thirds the way around but actuating the sunroof several times will move the lubricant around for you.) This was a common problem on several year models.