Diagnosis And Testing - Rear Wiper And Washer System

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.

WARNING:

To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, Occupant Classification System (OCS), seat belt tensioner, impact sensor or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to follow these instructions may result in accidental airbag deployment.

If the rear wiper motor operates, but the wiper motor output shaft does not move, replace the ineffective rear wiper motor. If the washer pump/motor operates, but no washer fluid is dispensed on the glass; or, if the wiper operates, but chatters, lifts, or does not clear the glass, clean and inspect the rear wiper and washer system components as required. Refer to CLEANING and Refer to INSPECTION .

The hard wired rear wiper and washer system circuits and components may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. For proper wire repair, and connector repair procedures. Refer to WIRE SPLICING or REMOVAL or INSTALLATION .

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls and 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.

NOTE:

The rear wiper and washer switches are integral to the right (wiper) multifunction switch in the Steering Column Control Module (SCCM). The multifunction switches communicate with the SCCM microcontroller. The SCCM microcontroller is a gateway to the Controller Area Network (CAN) data bus and communicates with the Body Control Module (BCM) over the CAN bus. The BCM controls rear wiper motor operation through the rear wiper relay that is integral to the Printed Circuit Board (PCB) within the BCM.

Before performing any of the following tests, determine whether the other functions of the SCCM multifunction switches are operational. If other SCCM switch functions are ineffective, diagnose and repair that problem before attempting to repair the rear wiper and washer system.

REAR WIPER AND WASHER SYSTEM DIAGNOSIS
CONDITION	POSSIBLE CAUSES	CORRECTION
WIPER MOTOR DOES NOT OPERATE IN ANY SWITCH POSITION	1. Ineffective motor ground circuit.	1. Test and repair open wiper motor ground circuit, if required.
	2. Ineffective motor feed circuits.	2. Test and repair motor feed circuit between BCM and rear wiper motor, if required.
	3. Ineffective SCCM inputs or outputs.	3. Use a diagnostic scan tool and the appropriate diagnostic information for additional SCCM diagnosis.
	4. Ineffective BCM inputs or outputs.	4. Use a diagnostic scan tool and the appropriate diagnostic information for additional BCM diagnosis.
	5. Ineffective wiper motor.	5. Test and replace open or shorted wiper motor, if required.
WIPER DOES NOT PARK CORRECTLY	1. Ineffective wiper motor park switch input circuit.	1. Test and repair wiper park switch input circuit between BCM and rear wiper motor, if required.
	2. Ineffective BCM inputs or outputs.	2. Use a diagnostic scan tool and the appropriate diagnostic information for additional BCM diagnosis.
	3. Ineffective wiper motor park switch.	3. Test and replace rear wiper motor, if required.
WIPER MOTOR OPERATES SLOWLY	1. Ineffective wiper motor.	1. Check amperage draw with wiper arm disconnected from rear wiper motor output shaft. Correct draw should be about 6 amperes. If incorrect, refer to the appropriate Possible Cause that follows:
	2. Amperage draw too low.	2. Test and repair shorted rear wiper motor signal and fused ignition switch output (RUN - ACCESSORY) circuits, if required.
	3. Amperage draw too high.	3. With wiper arm disconnected from wiper motor output shaft check for binding between output shaft and motor output shaft housing. If binding is detected, lubricate, if required. If no binding is detected, replace the wiper motor, if required.
WASHER PUMP DOES NOT OPERATE	1. Ineffective washer pump ground circuit.	1. Test and repair open washer pump ground circuit, if required.
	2. Ineffective washer pump feed circuit.	2. Test and repair washer pump feed circuit between BCM and washer pump if required.
	3. Ineffective SCCM inputs or outputs.	3. Use a diagnostic scan tool and the appropriate diagnostic information for additional SCCM diagnosis.
	4. Ineffective BCM inputs or outputs.	4. Use a diagnostic scan tool and the appropriate diagnostic information for additional BCM diagnosis.
	5. Ineffective washer pump.	5. Test and replace open or shorted washer pump, if required.