I suggest removing the passenger side underdash panel and slapping the motor. If it comes on, then it is probably the motor brushes. If it doesn't, remove it and jump 12 volts across the motor to see if it comes on. Be careful when you do this, it will jump out of your hand from the sudden torque.

If it does come on with jumped voltage, see if the connector is making voltage, then trace it back from there.

Good luck,