Inspection Procedure G-1

Windshield wiper and washer: Windshield wiper does not operate.

Windshield Wiper Motor Drive Circuit:

Connectors:

CIRCUIT OPERATION
- A signal from the windshield wiper switch is sent through the column-ECU inside the column switch to the front-ECU. The signal turns on the relay inside the front-ECU to operate the wiper motor.
- If the SWS communication line is defective, another signal line (wiper back-up circuit) will be active. In that case, the windshield wiper will operate at low-speed when the windshield wiper switch is in the "LOW" or "HIGH" position.

TECHNICAL DESCRIPTION (COMMENT)
If the windshield wiper does not work at all, the 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 and connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Check method of the input signal

Q: Which is to be used, the scan tool or the voltmeter to check the input signal?

Scan tool MB991502: Go to Step 2.
Voltmeter: Go to Step 3.

STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signals from the windshield wiper switches.

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.




1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sounds when the input signal enters?

YES: Go to Step 4.
NO: Check the windshield wiper switch input circuit. Refer to Inspection Procedure O-16.

STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the windshield wiper switches.




1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES: Go to Step 4.
NO: Check the windshield wiper switch input circuit. Refer to Inspection Procedure O-16.




STEP 4. Check the windshield wiper motor.
1. Disconnect the wiper motor connector A-03.
2. Connect a battery to the wiper motor as shown in the illustration and check motor operation at low-speed and high-speed.

Q: Is the wiper motor in good condition?

YES: Go to Step 5.
NO: Replace the wiper motor. The windshield wiper should work normally.

STEP 5. Check the wiper motor ground circuit at wiper motor connector A-03.
1. Disconnect wiper motor connector A-03 and measure at the harness side.




2. Measure the resistance between terminal 5 and ground.

Q: Is the resistance less than 2 ohm?

YES: Go to Step 8.
NO: Go to Step 6.




STEP 6. Check wiper motor connector A-03 for damage.

Q: Is wiper motor connector A-03 in good condition?

YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. The windshield wiper should work normally.




STEP 7. Check the harness wire between wiper motor connector A-03 and ground.

Q: Is the harness wire between wiper motor connector A03 and ground in good condition?

YES: There is no action to be taken.
NO: Repair it. The windshield wiper should work normally.

STEP 8. Check the front-ECU power supply circuit [ignition switch (ACC)] at the front-ECU connector A-09X.
1. Disconnect the front-ECU connector A-09X and measure at the relay box side.
2. Turn the ignition switch to "ACC" position.




3. Measure the voltage between terminal 9 and ground.

Q: Is the voltage approximately 12 volts (battery positive voltage)?

YES: Replace the front-ECU. The windshield wiper should work normally.
NO: Go to Step 9.




STEP 9. Check front-ECU connector A-09X for damage.

Q: Is front-ECU connector A-09X in good condition?

YES: Go to Step 10.
NO: Repair or replace it. Refer to Harness Connector Inspection. The windshield wiper should work normally.










STEP 10. Check the harness wires between front-ECU connector A-09X and ignition switch (ACC).

NOTE: After checking intermediate connector C-209 and junction block connectors C-303 and C-301, check the wires. If intermeditate connector C-209 and junction block connectors C-303 and C-301 are damaged, repair or replace them. Refer to Harness Connector Inspection.

Q: Are the harness wires between front-ECU connector A-09X and ignition switch (ACC) in good condition?

YES: There is no action to be taken.
NO: Repair them. The windshield wiper should work normally.