High Speed Windshield Wipers
When the wiper switch is set to the HIGH speed position, it supplies ground to the high/low speed relay coil and the high speed inputs of the internal windshield wiper module, which causes the windshield wiper motor to cycle at high speed. During high speed operation, the internal run/park and high/low relays are both activated, and supply 12 volts to the internal low and high speed inputs of the windshield wiper motor. The high/low speed relay coil ground is hard-wired to and controlled by the wiper switch, while the run/park relay coil ground is controlled by the internal windshield wiper module based on inputs received from the wiper switch. Since the high/low relay is controlled by the position of the wiper switch, the windshield wipers will still operate in high speed mode if the internal windshield wiper module fails, but will not automatically park when the wiper switch is turned to the OFF position.