Inspection Procedure G-1
Windshield Wiper Motor Driver 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 "LO" 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 windshield 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 the input signal.
Check the input signals from the windshield wiper switch.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "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.
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.
If a defect appears, check the windshield wiper switch input circuit. Refer to Inspection Procedure O-18.
If no defect appears, go to Step 2.
STEP 2. 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.
If the wiper motor is damaged, replace the wiper motor. The windshield wiper should work normally.
If the wiper motor is in good condition, go to Step 3.
STEP 3. Check the wiper motor ground circuit at the wiper motor connector A-03.
1. Disconnect the wiper motor connector A-03 and measure at the harness side.
2. Resistance between terminal 5 and ground.
- Should be less than 2 Ohms.
If open circuit, go to Step 4.
If less than 2 Ohms. go to Step 6.
STEP 4. Check the wiper motor connector A-03 for damage.
If the wiper motor connector A-03 is damaged, repair or replace it. Refer to Harness Connector Inspection. The windshield wiper should work normally.
If the connector is in good condition, go to Step 5.
STEP 5. Check the harness wire between wiper motor connector A-03 and ground.
If the harness wire between wiper motor connector A-03 and ground is damaged, repair it.
The windshield wiper should work normally.
STEP 6. 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. Voltage between terminal 9 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).
If not approximately 12 volts, go to Step 7.
If approximately 12 volts replace the front-ECU.
The windshield wiper should work normally.
STEP 7. Check the front-ECU connector A-09X for damage.
If the front-ECU connector A-09X is damaged, repair or replace it. Refer to Harness Connector Inspection.
The windshield wiper should work normally.
If the connector is in good condition, go to Step 8.
STEP 8. Check the harness wires between front-ECU connector A-09X and ignition switch (ACC).
NOTE: After checking intermediate connector C-89 and junction block connector C-101 and C-109, check the wires. If intermediate connector C-89 and junction block connector C-101 and C-109 are damaged, repair or replace them. Refer to Harness Connector Inspection.
If the harness wires between front-ECU connector A-09X and ignition switch (ACC) are damaged, repair them.
The windshield wiper should work normally.