The Mercury Mountaineer features a rear windshield wiper that allows the driver to clean the rear window to improve visibility. The wiper blade is attached to a small motor located in the rear lift door. The wiper blade may become brittle over time as it ages and fail to clean the window properly. The blade should be replaced as part of a routine maintenance plan. The rear wiper motor can also fail, which will cause the wiper blade not to move at all. Replacing the rear wiper motor requires removing the lift gate panel to access the small motor.
Turn the rear wiper on and check to see if the wiper motor is working properly. If the wiper blade moves across the window but does not clean the window, you need to install a new wiper blade. If the wiper motor does not move the wiper blade at all, the wiper motor may need to be replaced.
Replace the wiper blade by removing the existing blade. If the model year is 1997 or earlier, pull the wiper arm towards you until it is resting a few inches away from the window. Pull the arm off the spindle and install a new wiper blade. For 1998 and later models, lift off the cover from the pivot point on the wiper with a screwdriver and remove the retaining nut using a socket wrench. Replace the wiper blade and install the wiper arm.
Replace the rear wiper motor if required. Disconnect the negative battery cable with an adjustable wrench. Refer to step 2 and remove the wiper blade.
Remove the rear lift gate trim panel by removing the screws located on the handle with a screwdriver. Pry off the lock trim and remove the screw below the lock. Pry out the plastic rivets on the top of the trim panel using a trim tool available at most auto part stores. Remove the lift gate trim and set aside.
Detach the wiper motor bracket bolts using a socket wrench and remove the motor. Detach the electrical connector from the wiper motor.
Install a new wiper motor using a socket wrench to secure the bracket bolts. Reattach the electrical connector to the wiper motor.
Install the lift gate trim panel using the plastic rivets. Install the three retaining screws by the lock and handle using a screwdriver.
Reconnect the negative battery cable using an adjustable wrench. Turn the rear wiper on to make sure it is working properly.
