The front wiper mechanism with electric motor for the Toyota Prius III features a distinctive passenger-side wiper arm design with a double joint. This construction provides effective windshield coverage but also has several specific wear points that can eventually affect the mechanism and motor.
How long does replacement take?
- Experienced mechanic in a workshop: approximately 30-40 minutes.
- First-time DIY replacement: approximately 1 hour.
Why does the Prius III wiper mechanism and motor fail?
- Broken plastic joint bushings - the most common problem: The mechanism linkages are connected using plastic ball-joint bushings. When these bushings wear out or break, the linkage can disconnect from the drive mechanism. As a result, the driver's side wiper continues to operate while the passenger-side wiper stops moving completely.
- Seized passenger-side arm bearings: Due to the more complex double-joint construction, the small bearings on the passenger side can be exposed to moisture and eventually seize. This creates increased resistance and places excessive load on the electric motor.
- Incorrect parking position: The position sensor inside the motor, commonly known as the park switch, can eventually fail. When this happens, the wipers may stop in the middle of the windshield instead of returning to their normal parked position.
- Complete motor failure: If the mechanism joints become corroded and seize, the electric motor continues trying to move them. The resulting excessive load can cause the motor to overheat and eventually burn out its internal windings.
How is the wiper mechanism replaced?
- Mark the wiper position: Before starting, use masking tape to mark the current position of the wiper blades on the windshield. This helps ensure that the new mechanism and wiper arms are installed at the correct height.
- Remove the wiper arms: Remove the plastic caps, undo the 14 mm retaining nuts and carefully work the wiper arms off the shafts. The passenger side has two retaining nuts.
- Remove the side trim and plastic cowl: Carefully remove the small plastic corner pieces near the fenders, release the retaining clips and remove the long plastic trim panel beneath the windshield.
- Remove the complete mechanism: Undo the four 10 mm bolts securing the metal mechanism frame to the vehicle body. Disconnect the electrical connector from the motor and remove the complete wiper linkage assembly.
- Transfer the motor if necessary: If replacing only the mechanism without a motor, remove the three motor mounting bolts and transfer the original motor to the new mechanism. Take care not to alter the initial position of the linkage.
- Reassemble: Install and secure the mechanism and reconnect the electrical connector. Before reinstalling the plastic trim, briefly operate the wipers so that the motor returns to its correct park position. Then install the wiper arms according to the tape marks and tighten the retaining nuts.
