INSPECTION PROCEDURE 9: Blower Motor power supply system: Diagnosis

WARNING: This page is about a different variant/trim than selected.

Required Special Tools:

MB991223: Harness Set
MB992006: Extra Fine Probe

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?
1. YES: Go to Step 2.
2. NO: Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .

STEP 2. Check the blower relay continuity.

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

VOLTAGE SPECIFICATION

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: Checking Blower Relay Continuity
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

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?
  1. YES: Go to Step 5.
  2. NO: Go to Step 4.
    
    Fig 3: Measuring Voltage Between Terminals 4 And Ground
    Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
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 .
- 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?
  1. YES: It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
  2. NO: Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .
STEP 5. Check blower relay connector C-115 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is blower relay connector C-115 in good condition?
1. YES: Go to Step 6.
2. NO: Repair or replace the connector. Refer to HARNESS CONNECTOR INSPECTION .
STEP 6. Check the wiring harness between blower relay connector C-303 (terminal 3) and blower motor connector C-115 (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 .
- 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-115 (terminal 1) in good condition?
  1. YES: It can be assumed that this malfunction is intermittent. Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
  2. NO: Repair or replace the wiring harness. Refer to HARNESS CONNECTOR INSPECTION .