Windshield Wiper Systems
Troubleshooting a windshield wiper system begins with a visual inspection of the system. It may quickly reveal the problem. Windshield wiper systems often use circuit breakers to prevent overloaded circuits, temporarily disabling the wiper system. The system's problem is the motor's circuit breaker resetting.
Windshield Wiper Motors: Another common problem lies in the bolts that mount the motor to the chassis. The electrical ground of so many windshield wiper systems is completed through the mounting bolts to the vehicle chassis. As this connection wears or becomes rusty or corroded, the ground becomes loose. This looseness causes an intermittent ground condition that eventually results in no operation at all.
The motor and reduction gearing itself wears out. If you can tap lightly on it with a wrench and it starts working, it may be that it's completing the ground, but it may also be the motor itself is worn. Most motors are permanent magnet with brushes placed around a commutator. They contain a parking circuit that applies power to the motor until the blades are at the base of the window. A depressed parking system lowers the blades a little more, dropping them below the hood.
Linkage: One of the most common causes of dragging wiper blades or no operation of a windshield wiper system is faulty linkage. It must overcome the resistance of the wipers sweeping across the windshield. In time, the linkage loosens at the joints or separates and comes apart, causing failure in one or both wiper arms.
Switch and Wiring: Inspect the switch, relay, wiring, and module to ensure that the wiper motor is receiving power. There are many different wiper switches and options. Most switches contain a high, an intermittent, and a low-speed option.