FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Inspection Procedure G-7

Windshield Wiper and Washer: Windshield Washer does not Work.

Windshield Washer Motor Circuit Part 1:




Windshield Washer Motor Circuit Part 2:






NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor." How To Use SWS Monitor

CIRCUIT OPERATION
The windshield washer switch sends a signal through the column-ECU (incorporated in the column switch) to the front-ECU. If the column-ECU sends a windshield washer switch "ON" signal to the front-ECU, the front-ECU turns on the relay (incorporated in the front-ECU), thus causing the windshield washer motor to be turned on.

TECHNICAL DESCRIPTION (COMMENT)
If the windshield washer does not work normally, the windshield washer motor, the column switch (windshield wiper and washer switch) or the front-ECU may be defective.

TROUBLESHOOTING HINTS
- The windshield washer motor may be defective
- The column switch (windshield wiper and washer switch) may be defective
- The front-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface (V.C.I.)
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B
- MB991813: SWS monitor kit
- MB991806: SWS monitor cartridge
- MB991812: SWS monitor harness (for column-ECU)
- MB991922: Probe harness

STEP 1. Verify the windshield wiper.

Q: Does the windshield wiper operate normally?

YES: Go to Step 2.

NO: Refer to Inspection Procedure G-1 "Windshield wiper does not work at all."

STEP 2. Use scan tool MB991958 to select "ECU COMM CHK" on the SWS monitor display.
Check the following ECUs:
- Column-ECU
- Front-ECU

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. Connect special tool MB991910 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.







1. Connect the special tool. Refer to "How to connect SWS monitor." How to Connect SWS Monitor
2. Turn the ignition switch to the "ON" position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check."

4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" menus for both the "COLUMN ECU" and the "FRONT ECU" menus.

Q: Are "OK" displayed on the "COLUMN ECU" and "FRONT ECU" menu?

"OK" are displayed for all the items: Go to Step 3.
"NG" is displayed on the "COLUMN ECU" menu: Refer to Inspection Procedure A-2 "Communication with column switch (column-ECU) is not possible."
"NG" is displayed on the "FRONT ECU" menu: Refer to Inspection procedure A-4 "Communication with front-ECU is not possible."

STEP 3. Check the input signal by using "FUNCTION DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
- Ignition switch: ACC
- Windshield washer switch: ON







1. Operate scan tool MB991958 according to the procedure below to display "F.WIPER WASH."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "WIPER."
g. Select "F.WIPER WASH."




2. Check that normal conditions are displayed for the items described in the table.

Q: Are normal conditions displayed for "FRONT WASH.SW" and "FRONT ECU ACK"?

Normal conditions displayed for all the items: Go to Step 4.
Normal condition is not displayed for the "FRONT WASH.SW": Normal condition is not displayed on the "FRONT WASH.SW": Replace the column switch. Verify that the windshield washer works normally.
Normal condition is not displayed for the "FRONT ECU ACK": Normal condition is not displayed on the "FRONT ECU ACK": Replace the front-ECU. Verify that the windshield washer works normally.




STEP 4. Check windshield washer motor connector A-33 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is windshield washer motor connector A-33 in good condition?

YES: Go to Step 5.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the windshield washer works normally.

STEP 5. Check the windshield washer motor.




1. Disconnect windshield washer motor connector A-33 and measure the voltage available at the windshield washer motor side of the connector.
2. Fill the windshield washer tank with washer fluid.




3. When battery voltage is applied between terminals 1 and 2, washer fluid should gush out.

Q: Does the windshield washer motor operate normally?

YES: Go to Step 6.

NO: Replace the windshield washer motor. Verify that the windshield washer works normally.

STEP 6. Check the ground circuit to the windshield washer motor. Measure the resistance at windshield washer motor connector A-33.




1. Disconnect windshield washer motor connector A-33 and measure the resistance available at the wiring harness side of the connector.




2. Measure the resistance value between terminal 2 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 8.

NO: Go to Step 7.




STEP 7. Check the wiring harness between windshield washer motor connector A-33 (terminal 2) and ground.

Q: Is the wiring harness between windshield washer motor connector A-33 (terminal 2) and ground in good condition?

YES: No action is necessary and testing is complete.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the windshield washer works normally.




STEP 8. Check front-ECU connector A-11X for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is front-ECU connector A-11X in good condition?

YES: Go to Step 9.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Verify that the windshield washer works normally.










STEP 9. Check the wiring harness between windshield washer motor connector A-33 (terminal 1) and front-ECU connector A-11X (terminal 21).

NOTE: Also check intermediate connectors C-06 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-06 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection.

Q: Is the wiring harness between windshield washer motor connector A-33 (terminal 1) and front-ECU connector A-11X (terminal 21) in good condition?

YES: No action is necessary and testing is complete.

NO: The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. Verify that the windshield washer works normally.