* The wiper motor is installed upside down.
* The linkage between the wiper motor and the wiper arms is reversed.
* The wiper transmission is damaged.
* The wiper motor wiring is incorrect.
To diagnose the problem:
1. Check the wiper motor installation. The motor should be mounted with the shaft facing up.
2. Check the linkage between the wiper motor and the wiper arms. The linkage should be connected so that the wiper arms move up when the motor turns clockwise.
3. Check the wiper transmission. The transmission gears should be correctly meshed and not damaged.
4. Check the wiper motor wiring. The wiring should be connected according to the wiring diagram.
To repair the problem:
* If the wiper motor is installed upside down, reinstall it with the shaft facing up.
* If the linkage between the wiper motor and the wiper arms is reversed, reverse it so that the wiper arms move up when the motor turns clockwise.
* If the wiper transmission is damaged, replace it.
* If the wiper motor wiring is incorrect, correct it according to the wiring diagram.
