INSPECTION
PROCEDURE 4: The blower does not work <Front side>
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COMMENTS ON TROUBLE SYMPTOM
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If the blower motor does not operate, the blower motor circuit system may be defective.
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- Malfunction of the fuse
- Malfunction of the fusible link
- Malfunction of the blower motor
- Malfunction of the blower relay
- Malfunction of the power transistor
- Malfunction of the heater controller assembly (A/C-ECU)
- Damaged wiring harness or connectors
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STEP 1. M.U.T.-III CAN bus diagnostics.
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting  ).
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STEP 2. M.U.T.-III diagnosis code.
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Check that the diagnosis code related to the air conditioner is not set (Refer to ).
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Q.
Is the diagnosis code set?
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Carry out the diagnosis code procedures.
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Go to Step 3.
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STEP 3. M.U.T.-III diagnosis code for other systems.
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Use M.U.T.-III to check that the diagnosis code is set in the engine-ECU (Refer to GROUP
13B - Diagnosis code chart <6B3> or
Refer to GROUP 13C - Diagnosis code chart <4N1>).
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Q.
Is the diagnosis code set?
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Carry out the diagnosis for the diagnosis code.
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Go to Step 4.
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STEP 4. Check the data list below on the M.U.T.-III.
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All the following items in the data list should be normal.
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Item No.68: Front blower fan
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Q.
Is the check result normal?
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Go to Step 5.
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Go to Step 6.
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STEP 5. Replace the trouble symptom.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Replace the heater controller assembly (A/C-ECU) (Refer to ).
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STEP 6. Check the fuse (23).
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Q.
Is the fuse (23) in good condition?
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Go to Step 7.
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Replace the fuse (23).
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STEP 7. Check the fusible link (2).
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Q.
Is the fusible link (2) in good condition?
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Go to Step 9.
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Go to Step 8.
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STEP 8. Check open and short circuit in fusible link line between
fuse (23) and fusible link (2).
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Q.
Is the check result normal?
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Replace the fusible link (2).
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Repair or replace the connector(s) or wiring harness.
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STEP 9. Check the blower relay.
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Refer to .
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Q.
Is the blower relay in good condition?
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Go to Step 10.
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Replace the blower relay.
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STEP 10. Check the blower motor.
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Refer to GROUP 55A - Blower Assembly and Resistor Inspection .
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Q.
Is the check result normal?
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Go to Step 11.
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Replace the blower motor (Refer to GROUP 55A - Blower Assembly and Resistor ).
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STEP 11 Voltage measurement at blower motor connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal 1 and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 13.
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Go to Step 12.
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STEP 12. Check open circuit in blower motor line between blower relay
and blower motor.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 13. Voltage measurement at heater controller assembly (A/C-ECU)
connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal P/TC and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 15.
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Go to Step 14.
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STEP 14. Check open circuit in P/TC line between blower motor and
heater controller assembly (A/C-ECU) P/TC terminal.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 15 Voltage measurement at power transistor connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal 2 and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 17.
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Go to Step 16.
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STEP 16. Check open circuit in power transistor line between blower
motor and power transistor connector.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 17. Voltage measurement at heater controller assembly (A/C-ECU)
connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal BASE and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 19.
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Go to Step 18.
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STEP 18. Check open circuit in BASE line between power transistor
and heater controller assembly (A/C-ECU) BASE terminal.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 19. Resistance measurement at the power transistor connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Continuity between terminal 1 and body earth
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 21.
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Go to Step 20.
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STEP 20. Check open circuit in power transistor earth line between
power transistor connector and body earth.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 21. Resistance measurement at the blower relay connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Continuity between terminal 2 and body earth
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 23.
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Go to Step 22.
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STEP 22. Check open circuit in blower relay earth line between blower
relay connector and body earth.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 23. Resistance measurement at the heater controller assembly
(A/C-ECU) connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Continuity between terminal E and body earth
OK: Continuity exists (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 25.
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Go to Step 24.
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STEP 24. Check of open circuit in E line between heater controller
assembly (A/C-ECU) connector E terminal and body earth.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 25. Replace the power transistor (Refer to ), and
then recheck the trouble symptom
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Q.
Is the check result normal?
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This diagnosis is complete.
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Replace the heater controller assembly (A/C-ECU) (Refer to ).
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