You've got to determine if you are getting power to the fan motor.
First, make sure all fuses are good (the other things on that circuit would not be working if a fuse had popped).
Then check the leads coming into the fan motor for 12V
(with the switch on).
If nothing, then pull the switch from the wall, make sure the connections are good (might have vibrated loose over the last 26 years) and then check to see that it is getting power into the switch.
If you are getting power all the way to the motor but the motor isn't running then it sounds like a bad motor.