The wiper motor in your vehicle may begin to squeak over time. This is often the first sign that the motor is wearing down and is about to die. The wiper motor on automobiles are sealed units that require little to no servicing. The only ways to fix a windshield wiper motor is to lubricate the pivot arm or replace the entire motor if it fails. Replacement motors can be purchased from most auto parts stores if it becomes apparent that replacement will be necessary.
Open the bonnet and locate the wiper motor on your vehicle. Usually, it will be bolted to the firewall on the passenger side of the vehicle.
Turn on the windshield wipers and spray WD-40 on the wiper arm to pivot arm connection. Make sure you also lubricate the joint that connects the pivot arm to the wiper motor with WD-40. If the squeaking does not go away, then you will want to replace the motor.
Turn off the windshield wipers.
Unplug the electrical connector from the wiper motor.
Remove the bolts holding the wiper motor to the pivot arm.
Slide the wiper motor off the pivot arm and install the new motor. Installation is the reverse of removal.
For specific information about fixing your vehicle's wiper motor, consult the particular vehicle's manual.