Principles of Operation

PRINCIPLES OF OPERATION

Windshield Wiper Operation
The smart junction box (SJB) supplies power to the multifunction switch from the SJB fuse 25 (20A) when the ignition switch is in the ON or ACC position. The multifunction switch supplies power to the windshield wiper motor for the HIGH or LOW/INTERMITTENT input, depending on the multifunction switch position selected. The SJB also supplies power directly to the windshield wiper motor from fuse 25 (20A) when the ignition switch is in the ON or ACC position for RUN/PARK operation. When the multifunction switch is in the LOW, HIGH or INTERMITTENT position, power is supplied to the windshield wiper motor, which moves the wipers off the PARK position. Once the wipers are off the PARK position, an internal switch in the windshield wiper motor switches to the RUN/PARK position which directs power to the wiper switch then back to the wiper motor. This maintains power to the windshield wiper motor to complete the wipe cycle. When the cycle is complete, the internal switch in the windshield wiper motor switches back to the PARK position. If the multifunction switch is in the LOW or HIGH position, power is supplied from the multifunction switch and another wipe cycle starts. If the multifunction switch is in the INTERMITTENT position, the windshield wipers remain parked until the internal relay in the multifunction switch supplies power to the windshield wiper motor. The internal relay supplies power after a time delay that is determined by the 1 of 9 intermittent switch settings.

Rear Window Wiper Operation
The rear wiper motor is controlled by the SJB. The SJB supplies power to the rear wiper motor from the integrated rear wiper relay. The SJB will activate the relay when all of the following conditions are met:
- Ignition switch is in the ON position
- Liftgate glass and liftgate are closed
- Multifunction switch is in the ON or INTERMITTENT position

The SJB also supplies voltage to the rear wiper motor from SJB fuse 21 (10A) when the ignition switch is in the ON position. This power feed is used to continue the wipe cycle when the multifunction switch is turned to the OFF position. The SJB receives inputs from the multifunction switch that applies ground to the low speed wipe input or applies ground to the intermittent wipe input. When either of these circuits are grounded, the SJB activates the integrated rear wiper relay and power is supplied to the rear wiper motor to move the rear wiper motor from the PARK position. An internal switch in the rear wiper motor then moves to the RUN position which connects the accessory relay power to the rear wiper motor. When the rear wiper motor returns to the PARK position, the internal switch in the rear wiper motor moves back to the PARK position. If the multifunction switch is in the ON position, the rear wiper relay is still activated, power is supplied to the rear wiper motor, and the wipe cycle starts again. If the multifunction switch is in the INTERMITTENT position, the rear wiper relay does not activate until the predetermined dwell time has elapsed, at which time the SJB activates the rear wiper relay and the wipe cycle starts again.

Windshield Washer System
The SJB supplies power to the multifunction switch from fuse 25 (20A) when the ignition switch is in the ON or ACC position. The windshield washer pump receives power from the multifunction switch when the wash function is turned ON. The windshield washer pump has a direct ground to the chassis.

Rear Washer System
The SJB supplies power to the rear washer pump from fuse 21 (10A) when the ignition switch is in the ON or ACC position. The rear washer pump receives ground from the multifunction switch when the wash function is turned ON. The multifunction switch also signals the SJB when the rear wash is activated and the SJB then activates the rear wiper.