04 - Inspection Procedure
Blower Fan and Motor does not TurnBlower Motor Circuit:
Connectors:
CIRCUIT OPERATION
If the blower fan and motor does not turn when the blower switch is operated, the blower switch may be defective.
TROUBLESHOOTING HINTS
- Malfunction of the blower relay
- Malfunction of the blower switch
- Malfunction of the blower motor
- Damaged harness wires or connectors
DIAGNOSIS
Required Special Tools:
- MB991223: Test Harness Set
STEP 1. Check that the blower motor operates when the blower switch is moved to the "HI" position.
1. Ignition switch: ON
2. Blower switch: HI
Q: Does the blower motor operate when the blower switch is moved to the "HI" position?
YES: Refer to Inspection procedure 5 "Blower air amount cannot be changed."
NO: Go to Step 2.
STEP 2. Check the blower relay continuity.
Q: Is the blower relay continuity in good condition?
YES: Go to Step 3.
NO: Replace the blower relay. The blower motor should operate normally.
STEP 3. Check the blower fan and motor operation.
When battery voltage is applied between the terminals, check that the motor operates.
Q: Is there any abnormal noise?
YES: Go to Step 4.
NO: Replace the blower relay. The blower motor should operate normally.
STEP 4. Check the blower switch continuity.
Q: Is the blower switch continuity in good condition?
YES: Go to Step 5.
NO: Replace the blower switch. The blower motor should operate normally.
STEP 5. Measure the voltage at blower relay connector C-216.
1. Disconnect blower relay connector C-216, and measure the voltage at the junction block side.
2. Ignition switch: ON
3. Measure the voltage between terminal 1 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES: Go to Step 8.
NO: Go to Step 6.
STEP 6. Check blower relay connector C-216 for damage.
Q: Is blower relay connector C-216 in good condition?
YES: Go to Step 7.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. The blower motor should operate normally.
STEP 7. Check the wiring harness between blower relay connector C-216 and the ignition switch (IG1).
NOTE: Also check junction block connector C-211. If junction block connector C-211 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between blower relay connector C-216 and the ignition switch (IG1) in good condition?
YES: The blower motor should operate normally.
NO: Repair the wiring harness. The blower motor should operate normally.
STEP 8. Measure the resistance at blower relay connector C-216 in order to the ground circuit to the blower relay.
1. Disconnect connector C-216, and measure the resistance at the junction block side.
2. Measure the resistance value between terminal 3 and ground.
- 2 Ohm or less
Q: Does the measured resistance value correspond with this range?
YES: Go to Step 11.
NO: Go to Step 9.
STEP 9. Check blower relay connector C-216 for damage.
Q: Is blower relay connector C-216 in good condition?
YES: Go to Step 10
NO: Repair or replace the connector. Refer to Harness Connector Inspection.The blower motor should operate normally.
STEP 10. Check the wiring harness between blower relay connector C-216 and ground.
NOTE: Also check junction block connector C-214. If junction block connector C-214 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between blower relay connector C-216 and ground in good condition?
YES: The blower motor should operate normally.
NO: Repair the wiring harness. The blower motor should operate normally.
STEP 11. Measure the voltage at blower relay connector C-216.
1. Disconnect blower relay connector C-216, and measure the voltage at the wiring harness side.
2. Ignition switch: ON
3. Measure the voltage between terminal 5 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES: Go to Step 14.
NO: Go to Step 12.
STEP 12. Check blower relay connector C-216 for damage.
Q: Is blower relay connector C-216 in good condition?
YES: Go to Step 13.
NO: Repair or replace the connector. Refer to Harness Connector Inspection.The blower motor should operate normally.
STEP 13. Check the wiring harness between blower relay connector C-216 and fusible link 1.
NOTE: Also check intermediate connector C-126 and junction block connector C-212. If intermediate connector C-126 junction block connector C-212 are damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between blower relay connector C-216 and fusible link 1. in good condition?
YES: The blower motor should operate normally.
NO: Repair the wiring harness. The blower motor should operate normally.
STEP 14. Measure the voltage at blower switch connector C-125.
1. Disconnect blower switch connector C-125, and measure the voltage at the wiring harness side.
2. Ignition switch: ON
3. Measure the voltage between terminal 2 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES: Go to Step 17.
NO: Go to Step 15.
STEP 15. Check blower switch connector C-125 for damage.
Q: Is blower switch connector C-125 in good condition?
YES: Go to Step 16.
NO: Repair or replace the connector. Refer to Harness Connector Inspection.The blower motor should operate normally.
STEP 16. Check the wiring harness between blower switch connector C-125 and blower relay connector C-216.
NOTE: Also check junction block connector C-211. If junction block connector C-211 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between blower switch connector C-125 and blower relay connector C-216 in good condition?
YES: The blower motor should operate normally.
NO: Repair the wiring harness. The blower motor should operate normally.
STEP 17. Measure the voltage at blower motor connector C-08.
1. Disconnect blower motor connector C-08, and measure the voltage at the wiring harness side.
2. Ignition switch: ON
3. Blower switch: HI
4. Measure the voltage between terminal 1 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).
Q: Does the measured voltage correspond with this range?
YES: Go to Step 20.
NO: Go to Step 18.
STEP 18. Check blower motor connector C-08 for damage.
Q: Is blower motor connector C-08 in good condition?
YES: Go to Step 19.
NO: Repair or replace the connector. Refer to Harness Connector Inspection.The lower motor should operate normally.
STEP 19. Check the wiring harness between blower switch connector C-125 and blower motor connector C-08.
Q: Is the wiring harness between blower switch connector C-125 and blower motor connector C-08 in good condition?
YES: The blower motor should operate normally.
NO: Repair the wiring harness. The blower motor should operate normally.
STEP 20. Measure the voltage at blower motor connector C-08 in order to the ground circuit to the blower motor.
1. Disconnect blower motor connector C-08, and measure the voltage at the wiring harness side.
2. Measure the resistance value between terminal 2 and ground.
- 2 Ohm or less
Q: Does the measured resistance value correspond with this range?
YES: The blower motor should operate normally.
NO: Go to Step 21.
STEP 21. Check blower motor connector C-08 for damage.
Q: Is blower motor connector C-08 in good condition?
YES: Go to Step 22.
NO: Repair or replace the connector. Refer to Harness Connector Inspection.The blower motor should operate normally.
STEP 22. Check the wiring harness between blower motor connector C-08 and ground.
Q: Is the wiring harness between blower motor connector C-08 and ground in good condition?
YES: No action to be taken.
NO: Repair the wiring harness. The blower motor should operate normally.