Windshield Wiper Systems
Troubleshooting a windshield wiper system begins with a visual inspection of the system. It may reveal quite a bit about the problem. Windshield wiping systems often use circuit breakers to prevent overloaded circuits, temporarily disabling the wiper system. This means that the system’s problem may seem intermittent in nature, but actually be the breaker resetting.
Motor: 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 will become loose. This will cause an intermittent ground condition that will eventually result 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 will loosen at the joints or separate and come apart causing failure in one or both wiper arms. There are several different designs of linkage used in today’s vehicles. Most are tandem systems with two blades, one link in the middle. Some use a single blade or blades at opposite ends of the windshield.
Switch and Wiring: The switch, relay, wiring, and module must be inspected. This is to insure 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.