Operation

OPERATION

The washer pump/motor unit features a small Direct Current (DC) electric motor. The motor is connected to the vehicle electrical system through a single take out and two-cavity connector of the right (gasoline engines) or left (diesel engines) headlamp and dash wire harness. The motor is grounded at all times through another take out of the right (gasoline engines) or left (diesel engines) headlamp and dash wire harness. On vehicles with a gasoline engine, a single eyelet terminal connector is secured by a nut to a ground stud located on the right front fender inner shield in the engine compartment. On vehicles with a diesel engine, an eyelet terminal connector is secured by a ground screw to the left front fender inner shield in the engine compartment.

The motor receives battery current on a washer pump/motor control circuit. The washer pump/motor control circuit is energized through a high side driver within the Totally Integrated Power Module (TIPM) whenever the TIPM receives an electronic message requesting washer system operation from the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) over the Controller Area Network (CAN) data bus. The EMIC monitors a resistor multiplexed hard wired input from the momentary washer switch contacts within the multi-function switch on the steering column to determine when it should issue the electronic message requesting washer system operation.

Washer fluid is gravity-fed from the washer reservoir to the inlet side of the washer pump. When the pump motor is energized, the motor spins the rotor within the washer pump. The spinning pump rotor pressurizes the washer fluid and forces it through the pump outlet nipple, the washer plumbing, and the washer nozzles onto the windshield glass.

The washer pump/motor unit and the hard wired motor control circuits from the TIPM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the washer pump/motor unit or the electronic controls or communication between other modules and devices that provide some features of the wiper and washer system. The most reliable, efficient, and accurate means to diagnose the washer pump/motor unit or the electronic controls and communication related to washer pump/motor unit operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.