Pump, Windshield Washer: Operation: Headlamp

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

Headlamp washer pump/motor unit operation is completely controlled by the Body Control Module (BCM) logic circuits based upon electronic headlamp switch and washer switch status messages received from the microcontroller of the Steering Column Control Module (SCCM) over the Controller Area Network (CAN) data bus. The SCCM microcontroller monitors hard wired digital inputs from the headlamp switch circuitry of the left (lighting) multifunction switch and from the front washer switch circuitry of the right (wiper) multifunction switch to determine the proper status messages to send.

The headlamp washer relay control coil operates on ground received from the BCM, and the BCM will only allow the relay to function while the engine is running. In addition, the BCM will only allow the headlamp washers to operate when the headlamps are turned On. The BCM uses both a Low Side Driver (LSD) to energize or de-energize the headlamp washer relay in the Power Distribution Center (PDC) which, in turn, controls the operation of the headlamp washer pump/motor unit.

The hard wired circuits and components of the headlamp washer pump/motor unit 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 headlamp washer pump/motor or the electronic controls and communication between other modules and devices that provide some features of the headlamp washer system. The most reliable, efficient and accurate means to diagnose the headlamp washer pump/motor unit or the electronic controls and communication related to headlamp washer pump/motor unit operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.