- Problem with the windshield wiper switch: The windshield wiper switch is responsible for turning the wipers on and off. If the switch is faulty, it could cause the wipers to come on by themselves.
- Problem with the wiper motor: The wiper motor is responsible for powering the windshield wipers. If the motor is faulty, it could cause the wipers to come on by themselves.
- Problem with the wiring: The wiring that connects the windshield wiper switch and motor could also be faulty, causing the wipers to come on by themselves.
- Rain sensor malfunction: Some 1999 Ford Expeditions were equipped with rain sensors that automatically turn on the wipers when rain is detected. If the rain sensor is malfunctioning, it could cause the wipers to come on by themselves.
Troubleshooting
- Check to see if the windshield wiper switch is faulty by moving it back and forth. If the wipers come on when you move the switch, the switch is likely faulty and needs to be replaced.
- If the wipers do not come on when you move the switch, the problem may be with the wiper motor or wiring. You will need to remove the wiper motor and inspect it for damage. If the motor is damaged, it needs to be replaced.
- Check to see if the wiring between the windshield wiper switch and motor is damaged. If the wiring is damaged, it will need to be replaced.
- If the rain sensor is malfunctioning, it will need to be replaced.
