05 - Inspection Procedure

Blower Air Amount cannot be Changed

Blower Switch And Resistor Circuit:

CIRCUIT OPERATION
If the blower air amount can not be changed when the blower switch is operated, the blower switch may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the resistor
- Malfunction of the blower switch
- 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: Go to STEP 2.

NO: Refer to Inspection procedure 4 "Blower fan and motor does not turn."







STEP 2. Check the blower switch continuity.

Q: Is the blower switch continuity in good condition?

YES: Go to Step 3.

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

Standard Value:

STEP 3. Check the resistor resistance value.
Use an ohmmeter to measure the resistance between the terminals as indicated below. Check that the measured value is at the standard value.

Q: Is the measured value at the standard value?

YES: Go to Step 4.

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







STEP 4. Check blower switch connector C-125 and resistor connector C-09 for damage.

Q: Are blower switch connector C-125 and resistor connector C-09 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 switch connector C-125 and resistor connector C-09.

Q: Is the wiring harness between blower switch connector C-125 and resistor connector C-09 in good condition?

YES: Go to Step 6.

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




STEP 6. Check resistor connector C-09 and blower motor connector C-08 for damage.

Q: Are resistor connector C-09 and blower motor connector C-08 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 motor connector C-08 and resistor connector C-09.

Q: Is the wiring harness between resistor connector C-09 and blower motor connector C-08 in good condition?

YES: No action to be taken.

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