I have a 1999 Pontiac Sunfire with a sliding sunroof. I have two options when it comes to opening the sunroof. When I press the button once, it pops up in the back to vent. When I press it a second time, it is supposed to slide open.
Lately, it hasn't always been sliding completely open. Instead, it will only slide open about an inch or so and then stop. I cannot get it to finish sliding open even after pressing the button again. It usually closes fine; however, sometimes it won't close all the way and I have to keep pressing the button. My main concern is that it only slides open just an inch and stops. It even sounds a bit "rough" when it starts to slide, if that makes any sense.
I know it is not the switch because we already put a new one in, and it didn't make a difference. This problem is intermittent, almost like it has a mind of its own. It just started a week ago.
The headliner must be detached and lowered from the roof to gain access to the entire sunroof assembly. At this point all the components can be thoroughly inspected. It's basically comprised of a motor, an actuator (or transmission) and tracks that the glass rides on. There are also two switches used to automatically deactivate the motor when the glass reaches its fully open or closed position.
The intermittent operation you've described can be the result of a fault in a couple of areas -- the switches, the sunroof motor, the express module which controls the motor, a poor electrical connection or even something binding up in the actuator or tracks. The most common failure is the electric sunroof motor itself. But don't buy anything prior to a confirmation by a technician.
And it would not be a good idea to attempt replacing the sunroof motor yourself. It's a tricky procedure that involves "timing" the motor to the actuator, which can result in damage to the sunroof assembly if not done correctly.