Inspection Procedure F-1

Windshield Wiper and Washer: Windshield Wiper does no not Work at All

Windshield Wiper Motor Circuit:

Connectors:

NOTE: This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, refer to "How to use SWS monitor".

CIRCUIT OPERATION
- The windshield wiper and 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 wiper and washer switch "ON" signal to the front-ECU, the front-ECU turns on the relay (incorporated in the front-ECU), thus causing the windshield wiper and washer motor to be turned on.
- If the SWS communication line is defective, the front-ECU operates windshield wiper motor by using the other communication lines (wiper backup circuit) instead of that line. In this case, the windshield wiper works at low speed regardless of the windshield wiper and washer switch positions ("LO" or "HIGH").

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

TROUBLESHOOTING HINTS
- Malfunction of the wiper motor
- Malfunction of the column switch (windshield wiper and washer switch)
- Malfunction of the front-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991862: SWS monitor kit







STEP 1. Use scan tool to select "ECU CHECK" on the SWS monitor display.
Check the following ECUs:
- column-ECU
- front-ECU

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502. Also connect SWS monitor kit MB991862 after turning on scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Connect SWS monitor kit MB991862 to the column switch connector.
3. When the ignition switch is turned to the "ON" position, scan tool MB991502 should show "OK" on the "ECU CHECK" menu.

Q: Are "OK" displayed on the "COLUMN ECU" and "FRONT ECU"?
"OK" are displayed for all the items : Go to STEP 2.
"NG" is displayed on the "COLUMN ECU" menu : Refer to Inspection Procedure A-2 "Communication with column switch (column-ECU) is impossible."
"NG" is displayed on the "FRONT ECU" menu : Refer to Inspection procedure A-4 "Communication with front-ECU is impossible."










STEP 2. Check the input signal by using service data of the SWS monitor.
Check the input signals from the following switches:
- ignition switch: ACC
- windshield wiper switch: INT

Select "WIPER - F. WIPER INT" (FUNCTION DIAG.), and check that normal conditions are displayed on the items described in the table.

Q: Are normal conditions displayed on the "INT WIPER SW" and "FRONT ECU ACK"?

YES: Go to STEP 3.

NO:
- Normal condition is not displayed on the "INT WIPER SW: Replace the column switch. Check that the windshield wiper works normally.
- Normal condition is not displayed on the "FRONT ECU ACK": Replace the front-ECU. Check that the windshield wiper works normally.




STEP 3. Check the windshield wiper motor.
1. Disconnect windshield wiper motor connector B-01.
2. Connect a battery to the windshield wiper motor as shown.

Then check the windshield wiper motor operates normally at high and low speeds.

Q: Does the windshield wiper motor operate normally?

YES: Go to Step 4.

NO: Replace the windshield wiper motor. Check that the windshield wiper works normally.




STEP 4. Check at windshield wiper motor connector B-01 to check the windshield wiper motor ground circuit.
1. Disconnect windshield wiper motor connector B-01, and measure at the wiring harness side.
2. Measure the resistance value between terminal 5 and ground.
- The measured value should be 2 Ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 7.

NO: Go to Step 5.




STEP 5. Check windshield wiper motor connector B-01 for damage.

Q: Is windshield wiper motor connector B-01 in good condition?

YES: Go to Step 6.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the windshield wiper works normally.




STEP 6. Check the wiring harness between windshield wiper motor connector B-01 and ground.

Q: Is the wiring harness between windshield wiper motor connector B-01 and ground in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. Check that the windshield wiper works normally.





STEP 7. Measure at front-ECU connector A-11X in order to check the ignition switch (IG2) line of power supply system to the front-ECU.
1. Disconnect front-ECU connector A-11X, and measure at the relay box side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 30 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Does the measured voltage correspond with this range?

YES: Replace the front-ECU. Check that the windshield wiper works normally

NO: Go to Step 8.




STEP 8. Check the front-ECU connector A-11X for damage.

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

YES: Go to Step 9.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. Check that the windshield wiper works normally.













STEP 9. Check the wiring harness between front-ECU connector A-11X and the ignition switch (IG2).

NOTE: Also check intermediate connector C-129, junction block connectors C-210 and C-211 and joint connector C-101.
If intermediate connector C-129, junction block connector C-210 or C-211 or joint connector C-101 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between front-ECU connector A-11X and the ignition switch (IG2) in good condition?

YES: No action to be taken.

NO: Repair the wiring harness. Check that the windshield wiper works normally.