Ford Taurus 1999SE-Windshield wiper motor just hums.How to fix ?

Removal & Installation To Remove:

1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
2. Disconnect the battery ground cable.
3. Remove the wiper arms.
4. Remove the 8 plastic retainers and the 6 clips holding the cowl vent screens to the inner panels. Turn the retainers 1⁄4 turn counterclockwise to remove.
5. Remove the cowl vent screens.
6. Disconnect the electrical connector from the wiper motor and remove the 4 bolts that mount the module assembly to the cowl.
7. Remove the windshield wiper module from the vehicle.
8. Rotate the wiper operating arm in a clockwise direction to gain access to the bolt retaining the arm to the motor. WARNING
   Always rotate the wiper operating arm in a clockwise motion or damage to the motor could occur.
   
9. Remove the nut retaining the wiper operating arm to the wiper motor.
10. Remove the three wiper motor-to-wiper module assembly retaining bolts and remove the motor from the vehicle.

1. Position the wiper motor on to the module assembly. Install the three wiper motor-to-wiper module assembly retaining bolts. Tighten the bolts to 115-151 in lbs (13-17 Nm).
2. Position the wiper operating arm on the wiper motor output shaft. Install the mounting nut and tighten to 22-29 ft-lbs (30-40 Nm).
3. Position the windshield wiper module onto the cowl. Install the mounting bolts and tighten to 106 in-lbs (12 Nm).
4. Connect the wiper motor electrical connector.
5. Position the cowl vent screens onto the inner panels. Install the 8 plastic retainers and the 6 clips holding the cowl vent screens to the inner panels. Turn the retainers 1⁄4 turn counterclockwise to install.
6. Install the wiper arms.
7. Connect the battery ground cable.
8. Adjust wiper arms if necessary.