Inspection Procedure 13

INSPECTION PROCEDURE 13: Rear Blower Air Volume Cannot Be Changed.

Rear Blower Switch And Resistor Circuit:

CIRCUIT OPERATION
If the blower motor speed cannot be changed, the resistor circuit is suspected.

TROUBLESHOOTING HINTS
- Malfunction of the resistor
- Malfunction of the floor console rear A/C switch assembly
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tool:
- MB991223: Test Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check resistor connector C-21 for loose, corroded or damaged terminals, or terminals pushed back in the connector.






Q: Is resistor connector C-21 in good condition?

YES : Go to Step 2.

NO : Repair or replace the connector. The rear blower motor should operate normally.

STEP 2. Check the resistor operation.






1. Disconnect resistor connector C-21.






2. Use an ohmmeter to measure the resistance between the terminals. Check that the measured value is at the standard value.






Q: Is the measured value at the standard value?

YES : Go to Step 3.

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

STEP 3. Check floor console rear A/C switch assembly connector C-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector.






Q: Is floor console rear A/C switch assembly connector C-19 in good condition?

YES : Go to Step 4.

NO : Repair or replace the connector. The rear blower motor should operate normally.

STEP 4. Check the floor console rear A/C switch assembly operation.






1. Disconnect floor console rear A/C switch assembly connector C-19.






2. Follow the table below to check the floor console rear A/C switch assembly for continuity.






Q: Is the blower switch continuity in good condition?

YES : Replace the floor console rear A/C switch assembly. The rear blower motor should operate normally.

NO : Go to Step 5.

STEP 5. Check the wiring harness between resistor connector C-21 (terminal 1, 3 and 6) and floor console rear A/C switch assembly connector C-19 (terminal 5, 1 and 6).






- Check the resistor lines for open and short circuit.

Q: Is the wiring harness between resistor connector C-21 (terminal 1, 3 and 6) and floor console rear A/C switch assembly connector C-19 (terminal 5, 1 and 6) in good condition?

YES : It can be assumed that this malfunction is intermittent.

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