Inspection Procedure 5

Blower Fan and Motor does not Turn.

Blower Motor Circuit Part 1:

Blower Motor Circuit Part 2:

TECHNICAL DESCRIPTION (COMMENT)
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
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set

STEP 1. 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. Turn the ignition switch to the "ON" position.
3. Turn the blower switch to the "HI" position.




4. Measure the voltage between terminal 1 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts?

YES: Go to Step 17.

NO: Go to Step 2.







STEP 2. Check the blower relay continuity.
Follow the table to check the blower relay for 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. 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. Turn the ignition switch to the "ON" position.




3. Measure the voltage between terminal 1 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts?

YES: Go to Step 6.

NO: Go to Step 4.




STEP 4. Check blower relay connector C-216 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is blower relay connector C-216 in good condition?

YES: Go to Step 5.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. The blower motor should operate normally.




STEP 5. Check the wiring harness between blower relay connector C-216 (terminal 1) and the ignition switch (IG2).

NOTE: Also check junction block connector C-211 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. 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 (terminal 1) and the ignition switch (IG2) in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Repair the wiring harness. The blower motor should operate normally.

STEP 6. Measure the resistance at blower relay connector C-216.




1. Disconnect connector C-216, and measure the resistance at the junction block side.




2. Measure the resistance value between terminal 3 and ground.
- The measured value should be 2 ohms or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 9.

NO: Go to Step 7.




STEP 7. Check blower relay connector C-216 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is blower relay connector C-216 in good condition?

YES: Go to Step 8.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. The blower motor should operate normally.




STEP 8. Check the wiring harness between blower relay connector C-216 (terminal 3) and ground.

NOTE: Also check junction block connector C-214 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. 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 (terminal 3) and ground in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Repair the wiring harness. The blower motor should operate normally.

STEP 9. 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. Measure the voltage between terminal 5 and ground.
- The measured value should be approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts?

YES: Go to Step 12.

NO: Go to Step 10.




STEP 10. Check blower relay connector C-216 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is blower relay connector C-216 in good condition?

YES: Go to Step 11.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. The blower motor should operate normally.







STEP 11. Check the wiring harness between blower relay connector C-216 (terminal 5) and fusible link (1).

NOTE: Also check intermediate connector C-126 and junction block connector C-212 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-126 and junction block connector C-212 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between blower relay connector C-216 (terminal 5) and fusible link 1. in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Repair the wiring harness. The blower motor should operate normally.







STEP 12. Check blower switch connector C-125 and blower relay connector C-216 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is blower switch connector C-125 and 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 switch connector C-125 (terminal 2) and blower relay connector C-216 (terminal 4).

NOTE: Also check junction block connector C-211 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. 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 (terminal 2) and blower relay connector C-216 (terminal 4) in good condition?

YES: Go to Step 14.

NO: Repair the wiring harness. The blower motor should operate normally.







STEP 14. Check the blower switch continuity.
Follow the table to check the blower switch for continuity.

Q: Is the blower switch continuity in good condition?

YES: Go to Step 15.

NO: Replace the blower switch. The blower motor should operate normally.







STEP 15. Check blower switch connector C-125 and blower motor connector C-08 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is blower switch connector C-125 and blower motor connector C-08 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 (terminal 6) and blower motor connector C-08 (terminal 1).

Q: Is the wiring harness between blower switch connector C-125 (terminal 6) and blower motor connector C-08 (terminal 1) in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Repair the wiring harness. The blower motor should operate normally.




STEP 17. Check the blower fan and motor operation.

When battery voltage is applied between the terminals, check that the motor operates.

Q: Is the check result normal?

YES: Go to Step 18.

NO: Replace the blower motor. The blower motor should operate normally.

STEP 18. Measure the resistance at blower motor connector C-08.




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.
- The measured value should be 2 ohms or less.

Q: Does the measured resistance value correspond with this range?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Go to Step 19.




STEP 19. Check blower motor connector C-08 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is blower motor connector C-08 in good condition?

YES: Go to Step 20.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. The blower motor should operate normally.




STEP 20. Check the wiring harness between blower motor connector C-08 (terminal 2) and ground.

Q: Is the wiring harness between blower motor connector C-08 (terminal 2) and ground in good condition?

YES: It can be assumed that this malfunction is intermittent. Refer to How to Cope with intermittent Malfunctions.

NO: Repair the wiring harness. The blower motor should operate normally.