Inspection Procedure 5

INSPECTION PROCEDURE 5: Blower Air Amount cannot be Changed.

Blower Switch And Resistor Circuit:

FUNCTION
The air from the blower fan is cooled or warmed to control the temperature.

PROBABLE CAUSES
- Malfunction of the resistor
- Malfunction of the blower switch
- Malfunction of the harness.
- Malfunction of connector.

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check resistor connector C-106 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Is resistor connector C-106 in good condition?

YES : Go to Step 2.

NO : Repair or replace the connector.

STEP 2. Check the resistor resistance value.







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.

STEP 3. Check blower motor connector C-116 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Is blower motor connector C-116 in good condition?

YES : Go to Step 4.

NO : Repair or replace the connector.

STEP 4. Check the wiring harness for open circuit blower switch connector C-116 (terminal 1) and resistor connector C-106 (terminal 2).







Q: Is the wiring harness between blower switch connector C-116 (terminal 1) and resistor connector C-106 (terminal 2) in good condition?

YES : Go to Step 5.

NO : Repair the wiring harness.

STEP 5. Check blower switch connector C-12 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Is blower switch connector C-12 in good condition?

YES : Go to Step 6.

NO : Repair or replace the connector.

STEP 6. Check the blower switch continuity.







Follow the table below to check the blower switch for continuity.







Q: Is the blower switch continuity in good condition?

YES : Go to Step 7.

NO : Replace the heater control.

STEP 7. Check the wiring harness for open circuit blower switch connector C-12 (terminals 1, 6 and 2) and resistor connector C-106 (terminals 3, 1 and 4).







Q: Are the wiring harness between blower switch connector C-12 (terminals 1, 6 and 2) and resistor connector C-106 (terminals 3, 1 and 4) in good condition?

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

NO : Repair the wiring harness.