Sounds like the motor may not be getting voltage to run at all. The
original poster didn't say the motor was turning so this is just a
guess on my part. Check for voltage at the switch. If there is voltage
there, then actuate the switch and look for voltage on the other side
of the switch. If there is voltage there, actuate the switch while
looking for voltage at the motor. If there is voltage at the motor and
it's not turning, the motor is most likely bad. On my 89, there is a
relay in the sunroof circuit that located right next to the motor. If
there's no voltage at the motor but there is voltage at the switch,
this relay is most likely the fault (if there is one in your car).