Mitsubishi Grandis. Manual - part 316

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-149

INSPECTION PROCEDURE 21: Rear fan switch system <RHD>

COMMENTS ON TROUBLE SYMPTOM

If a rear fan switch signal is not set to the A/C-ECU, 
the rear fan switch or the rear fan switch circuit 
system may be defective.

POSSIBLE CAUSES

• Malfunction of the rear fan switch

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

DIAGNOSIS

Step 1. Connector check: C-19 rear fan switch

Q:  Is the check result normal?

IGNITION
SWITCH (IG2)

REAR
FAN
SWITCH

A/C-ECU

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Gray     R : Red     P : Pink     V : Violet

Rear Fan Switch Circuit

AC310631AI

Connector: C-19 <RHD>

Harness side

C-19 (GR)

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-150

YES : 

Go to Step 2.

NO : 

Repair the connector.

Step 2. Check the rear fan switch

 Refer to 

P.55-199

.

Q:  Is the check result normal?

YES : 

Go to Step 3.

NO : 

Replace the rear fan switch.

Step 3. Voltage measurement at C-19 rear fan 
switch connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Turn the ignition switch to the ON position.

(3) Measure the voltage between terminal 1 and 

body earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 4.

Step 4. Check the wiring harness between C-19 
rear fan switch connector terminal No.1 and the 
ignition switch (IG2).

NOTE: 

Prior to the wiring harness inspection, check joint 
connector C-01 and junction block connector C-205 
and C-202, and repair if necessary.

• Check the rear fan switch power supply line for 

open circuit.

Q: Is the check result normal?

AC310631AI

Connector: C-19 <RHD>

Harness side

C-19 (GR)

AC310507

Connector C-19 
(Harness side)

BD

AC310632AJ

Connectors: C-01, C-19 <RHD>

C-01

C-19 (GR)

C-01

C-19

Harness side

AC310619

Connectors: C-202, C-205 <RHD>

AF

Junction block (Front view)

C-205

C-202

C-205

Harness side

C-202

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-151

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction 

P.00-5

.)

NO : 

Repair the wiring harness.

Step 5. Connector check: C-104 A/C-ECU 
connector

Q:  Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the connector.

Step 6. Check the wiring harness between C-19 
rear fan switch connector terminal No.2 and 
C-104 A/C-ECU connector terminal No.71.

• Check the rear fan switch activating lines for 

open or short circuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 7. Recheck the trouble symptom

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00, How to 
Cope with Intermittent Malfunction 

P.00-5

.)

NO : 

Replace the A/C-ECU.

AC310631AH

Connector: C-104 <RHD>

Harness side

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AC310631AI

Connector: C-19 <RHD>

Harness side

C-19 (GR)

AC310631AH

Connector: C-104 <RHD>

Harness side

51

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TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-152

INSPECTION PROCEDURE 22: Rear blower motor power supply system <LHD>

CIRCUIT OPERATION

If the rear blower motor does not operate, the rear 
blower motor circuit system may be defective.

POSSIBLE CAUSES

• Malfunction of rear blower relay

• Malfunction of rear blower motor

• Malfunction of rear power transistor 

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

FUSIBLE
LINK

30

IGNITION
SWITCH (IG2)

FUSE BOX

REAR
BLOWER
RELAY

REAR
BLOWER
MOTOR

REAR
POWER
TRANSISTOR

A/C-ECU

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Gray     R : Red     P : Pink     V : Violet

Rear Blower Motor Circuit