What is the reason for one wiper moving while the other remains stationary?

[LaMason]

It may be due to a fault in the wiper motor's wiring. Here is some relevant information about wipers: 1. Working principle: When operating the wiper handle, the demand signal is transmitted to the BCM (Body Control Module), which then sends a start signal to the wiper motor. The wiper motor controls the wiper arm to perform the corresponding action. This is the working principle of the wiper. 2. Precautions: The wiring of the wiper's working principle differs from that of other electrical appliances. Other appliances turn off the positive pole (commonly known as the live wire), while the wiper wiring turns off the negative pole (commonly known as the ground wire or earth wire). This is why the wiper blade stops at the bottom of the windshield when the wiper switch is turned off at any position. Since the switch turns off the negative pole, if the wiper blade is turned off at another position, the C-shaped metal ring on the turbine inside the wiper assembly will still be connected to the car body, forming a working circuit. The wiper blade will continue to move until it reaches the opening of the C-shaped metal ring and stops.