INSPECTION
PROCEDURE 3: The blower does not work
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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 blower motor
- Malfunction of the power transistor
- Malfunction of the auto A/C 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.
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Q.
Is the diagnosis code set?
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Carry out the diagnosis code procedures. Refer to .
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Go to Step 3.
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STEP 3. Check the blower relay.
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Refer to GROUP 55A - Blower Assembly and Resistor .
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Q.
Is the blower relay in good condition?
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Go to Step 4.
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Replace the blower relay.
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STEP 4. Check open circuit in blower relay line between IG2 relay,
fusible link (2), and blower relay and body earth.
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Before the wiring harness check, check the junction block connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connector(s) or wiring harness.
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STEP 5. Check the blower motor.
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Refer to GROUP 55A - Blower Assembly and Resistor .
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Q.
Is the check result normal?
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Go to Step 6.
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Replace the blower motor.
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STEP 6. 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 7.
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Replace the blower motor.
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STEP 7. Check open circuit in blower motor line between blower relay,
blower motor and power transistor.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the connector(s) or wiring harness.
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STEP 8. 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 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 9.
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Repair the wiring harness wires between power transistor connector terminal and
body earth.
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STEP 9. Check open circuit in RVM, BASE and E line between power transistor,
body earth and auto A/C controller assembly (A/C-ECU).
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Q.
Is the check result normal?
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Go to Step 10.
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Repair the connector(s) or wiring harness.
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STEP 10. 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 Item No.69:Front blower fan (Target)
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Q.
Is the check result normal?
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Go to Step 11.
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Replace the auto A/C controller assembly (A/C-ECU).
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STEP 11. Replace the power transistor and recheck the trouble symptom
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Check that the blower motor operates normally.
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Q.
Is the check result normal?
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This diagnosis is complete.
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Replace the auto A/C controller assembly (A/C-ECU).
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