Rear Wipers and Washers

Rear Wipers and Washers

Description

An electrically operated fixed interval intermittent rear wiper and washer system is standard factory-installed equipment on this vehicle. The rear wiper and washer system includes the following major components, which are described in further detail elsewhere in this service information:

• ElectroMechanical Instrument Cluster - The ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) is located on the instrument panel directly in front of the driver.

• Multifunction Switch - The multifunction switch is secured to a bracket integral to the clockspring housing, on the top of the steering column just below the steering wheel. The multifunction switch is connected to the Steering Control Module (SCM), which is internal to the multifunction switch housing. Only the switch control stalk extending from the left side of the steering column is visible, while the remainder of the switch is concealed beneath the steering column shrouds. The multifunction switch is dedicated to providing all of the driver controls for both the front and rear wiper and washer systems. Refer to => [ Multifunction Switch ] Description and Operation.

• Rear Washer Nozzle - The fluidic rear washer nozzle is located on the liftgate spoiler above the liftgate glass. The rear washer nozzle includes an integral check valve.

• Rear Washer Plumbing - The plumbing for the rear washer system consists of rubber hoses and molded plastic fittings. The plumbing is routed along the right side of the engine compartment from the washer reservoir, through the dash into the passenger compartment, up the right cowl side and A-pillar where it is connected to a hose integral to the headliner that runs from the A-pillar to the rear washer nozzle hose on the upper liftgate opening header.

• Rear Washer Relay - The rear washer relay is an International Standards Organization (ISO) relay that is located within the Totally Integrated Power Module (TIPM) in the engine compartment near the battery.

• Rear Wiper Arm And Blade - The single rear wiper arm is secured by a nut directly to the rear wiper motor output shaft, which extends through the center of the liftgate glass near the base of the glass. The rear wiper blade is secured to the rear wiper arm with an integral latch, and is parked on the lower edge of the glass when the rear wiper system is not in operation.

• Rear Wiper Motor - The rear wiper motor includes the motor bracket, three rubber-isolated wiper motor mounts and the rear wiper motor. The wiper motor output shaft is the only visible component of the rear wiper motor. The remainder of the motor is concealed behind the liftgate trim panel beneath the liftgate glass opening.

Hard wired circuitry connects the rear wiper and washer system components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the rear wiper and washer system components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

Operation

The rear wiper and washer system is designed to provide the vehicle operator with a convenient, safe, and reliable means of maintaining visibility through the liftgate glass. The various components of this system are designed to convert electrical energy produced by the vehicle electrical system into the mechanical action of the wiper blade to wipe the outside surface of the glass, as well as into the hydraulic action of the washer system to apply washer fluid stored in an on-board reservoir to the area of the glass to be wiped. When combined, these components provide the means to effectively maintain clear visibility for the vehicle operator by removing excess accumulations of rain, snow, bugs, mud or other minor debris from the outer surface of the liftgate glass that might be encountered while driving the vehicle under numerous types of inclement operating conditions.






The vehicle operator initiates all front and rear wiper and washer system functions with the control sleeve (2) on the control stalk (3) of the multifunction switch that extends from the left side of the steering column, just below the steering wheel. Rotating the control sleeve to the OFF or INTERMITTENT detent positions or the momentary WASH position selects the rear wiper and washer system operating modes.

The multifunction switch provides hard wired analog and resistor multiplexed inputs to the Steering Control Module (SCM) integral and internal to the multifunction switch housing for all of the rear wiper and washer system functions. The SCM then sends electronic rear wiper/washer switch status messages to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) over a Local Interface Network (LIN) data bus. The EMIC then sends electronic rear wiper/washer switch request messages to the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus requesting the appropriate rear wiper and washer system operating modes.

The TIPM uses intelligent, high current, self-protected high side and low side drivers and a control output to the rear wiper relay, which provides battery voltage to operate the rear wiper motor for as long as the ignition switch is in the ACCESSORY or ON positions, plus a delay after the ignition switch is turned to any other position long enough to allow the rear wiper motor to park the rear wiper blade at the base of the liftgate glass. The TIPM uses front and rear washer relays to control the operation of the reversible washer pump/motor unit.

Rear wiper and washer system operation is completely controlled by the SCM, EMIC and TIPM logic circuits, and that logic will only allow these systems to operate when the ignition switch is in the ACCESSORY or ON positions. Battery current is directed from the TIPM to the rear wiper relay through a fused B(+) circuit. The multifunction switch circuitry receives a clean ground output from the SCM on a multifunction switch return circuit, then provides analog and resistor multiplexed inputs to the SCM to indicate the selected rear wiper and rear washer system mode.

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

Operating Modes

Following are paragraphs that briefly describe the operation of each of the rear wiper and washer system operating modes.

Intermittent Wipe Mode

When the INTERMITTENT WIPE position of the control sleeve on the control stalk of the multifunction switch is selected, the SCM sends an electronic rear wiper switch status message to the EMIC over the LIN data bus, then the EMIC relays an electronic rear wiper switch request message to the TIPM over the CAN data bus, then the TIPM energizes the rear wiper relay control coil. This directs battery current through the normally open contacts of the energized rear wiper relay to enable the rear wiper motor causing the wipers to cycle with a predetermined fixed delay interval between wiper sweeps.

Wash Mode

When the control sleeve of the multifunction switch is rotated to the momentary rear WASH position, the SCM sends an electronic rear washer switch status message to the EMIC over the LIN data bus, then the EMIC relays an electronic rear washer switch request message to the TIPM over the CAN data bus, then the TIPM energizes the rear washer relay, which directs battery current to the washer pump/motor unit while the de-energized front washer relay provides ground. This will cause the washer pump/motor unit to be energized in the rear wash direction for as long as the switch is held closed (up to about 10 seconds) and to be de-energized when the control knob is released. The washer pump is de-energized as soon as the control sleeve is released, but the rear wiper motor continues to operate for two to three continuous cycles before reverting to the fixed delay interval operation. The TIPM uses a hard wired output from a park switch internal to the rear wiper motor as an additional logic input to monitor the position of the rear wiper blade on the glass and to control the number of continuous wiper sweeps following washer operation.