INSPECTION PROCEDURE 3: The blower does not work


COMMENTS ON TROUBLE SYMPTOM
If the blower motor does not operate, the blower motor circuit system may be defective.

PROBABLE CAUSES

  • Malfunction of the blower motor
  • Malfunction of the power transistor
  • Malfunction of the heater controller assembly (A/C-ECU)
  • Damaged wiring harness or connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).

STEP 2. M.U.T.-III diagnosis code.
Recheck if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Ignition switch: LOCK (OFF) to ON
(3)Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Carry out the diagnosis code procedures. Refer to .
Go to Step 3.

STEP 3. Check the blower relay.
Refer to .

Q. Is the blower relay in good condition?
Go to Step 4.
Replace the blower relay.

STEP 4. Check the blower motor.
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the blower motor.

STEP 5. Voltage measurement at blower motor connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the ON position.
(3)Voltage between terminal 1 and body earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 6.
INSPECTION PROCEDURE 14: Refer to "Blower motor power supply system" .

STEP 6. Resistance measurement at the C-109 power transistor connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Continuity between terminal 1 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 7.
Repair the wiring harness wires between power transistor connector terminal No. 1 and body earth.

STEP 7. Check of open circuit in power transistor power supply line between blower motor and power transistor connector.

Q. Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.

STEP 8. Check of open circuit in P/TB and P/TC line between blower motor, power transistor and heater controller assembly (A/C-ECU) connector.

Q. Is the check result normal?
Go to Step 9.
Repair the connector(s) or wiring harness.

STEP 9. Replace the power transistor and recheck the trouble symptom
Check that the blower motor operates normally.

Q. Is the check result normal?
This diagnosis is complete.
Replace the heater controller assembly (A/C-ECU).