INSPECTION PROCEDURE 9: Blower Motor power supply system: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Check blower relay connector C-303 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is blower relay connector C-303 in good condition? 

   • YES:  Go to Step 2.
   • NO:  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .
2. STEP 2. Check the blower relay continuity. 

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

   Battery voltage	Tester connection	Specified condition
   Not applied	3 - 4	Open circuit
   Connect terminal 1 to the positive battery terminal Connect terminal 2 to the negative battery terminal	3 - 4	Less than 2 ohms

   Q: Is the blower relay in good condition? 

   • YES:  Go to Step 3.
   • NO:  Replace the rear window defogger relay.
     Fig 1: Identifying Blower Relay

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
3. STEP 3. Measure the voltage at blower relay connector C-303. 
   1. Disconnect blower relay connector C-303, and measure the voltage at the junction block side.
   2. Measure the voltage between terminals 1 and ground.
      • The measured value should be approximately 12 volts (battery positive voltage).
        Fig 2: Measuring Voltage Between Terminals 1 And Ground

        Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
   3. Measure the voltage between terminals 4 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 5.
   • NO:  Go to Step 4.
     Fig 3: Measuring Voltage Between Terminals 4 And Ground

     Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
4. STEP 4. Check the wiring harness between blower relay connector C-303 (terminals 1 and 4) and the fusible link (37). 
   NOTE: Also check ETACS-ECU connector C-309 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If ETACS-ECU connector C-309 is damaged, repair or replace the connector as described in Harness Connector Inspection, refer to HARNESS CONNECTOR INSPECTION .

   • Check the blower relay power supply line for open circuit.

   Q: Is the wiring harness between blower relay connector C-303 (terminals 1 and 4) and the fusible link (37) in good condition? 

   • YES:  It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
   • NO:  Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .
5. STEP 5. Check blower relay connector C-113 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is blower relay connector C-113 in good condition? 

   • YES:  Go to Step 6.
   • NO:  Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .
6. STEP 6. Check the wiring harness between blower relay connector C-303 (terminal 3) and blower motor connector C-113 (terminal 1). 
   NOTE: Also check ETACS-ECU connector C-315 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If ETACS-ECU connector C-315 is damaged, repair or replace the connector as described in Harness Connector Inspection, refer to Harness Connector Inspection, refer to HARNESS CONNECTOR INSPECTION .

   • Check the blower motor power supply line for open circuit.

   Q: Is the wiring harness between blower relay connector C-303 (terminal 3) and blower motor connector C-113 (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 or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .