Mitsubishi Grandis. Manual - part 321

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-169

YES : 

Go to Step 2.

NO : 

Repair the connector.

Step 2. Check the PTC heater switch.

 Refer to 

P.55-212

.

Q: Is the refrigerant temperature switch operating 

properly?

YES : 

Go to Step 3.

NO : 

Replace the refrigerant temperature switch.

Step 3. Voltage measurement at C-30 PTC heater 
switch connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

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

(3) Voltage between terminal 2 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-30 
PTC heater switch connector terminal No.2 and 
the ignition switch (IG2).

NOTE: 

Prior to the wiring harness inspection, check joint 
connector C-31 and junction block connector C-205 
and C-202, and repair if necessary.

• Check the PTC heater switch power supply line 

for open circuit.

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 : 

Repair the wiring harness.

AC310613

AM

Connector: C-30 <LHD>

Harness side

AC310507

Connector C-30 
(Harness side)

DJ

AC310613

AM

Connector: C-30 <LHD>

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

55-170

Step 5. Connector check: C-106 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-30 
PTC heater switch connector terminal No.1 and 
C-106 A/C-ECU connector terminal No.26.

• Check the PTC heater switch earth line for open 

circuit.

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 : 

Repair the wiring harness.

AC310613

AC

Connector: C-105 <LHD>

Harness side

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

AC310614

BG

Connectors: C-30, C-106 <LHD>

Harness side

C-30

C-106

C-30

C-106

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-171

INSPECTION PROCEDURE 25: PTC heater switch system <RHD>

COMMENTS ON TROUBLE SYMPTOM

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

POSSIBLE CAUSES

• Malfunction of the PTC heater switch

• Malfunction of the automatic air conditioner 

control panel (A/C-ECU)

DIAGNOSIS

Step 1. Connector check: C-30 PTC heater switch 
connector

Q: Is the check result normal?

IGNITION
SWITCH (IG2)

PTC
HEATER
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

PTC Heater Switch Circuit

AC310631AJ

Connector: C-30 <RHD>

Harness side

TROUBLESHOOTING

HEATER, AIR CONDITIONER AND VENTILATION

55-172

YES : 

Go to Step 2.

NO : 

Repair the connector.

Step 2. Check the PTC heater switch.

 Refer to 

P.55-212

.

Q: Is the refrigerant temperature switch operating 

properly?

YES : 

Go to Step 3.

NO : 

Replace the refrigerant temperature switch.

Step 3. Voltage measurement at C-30 PTC heater 
switch connector.

(1) Disconnect the connector, and measure at the 

wiring harness side.

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

(3) Voltage between terminal 2 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-30 
PTC heater switch connector terminal No.2 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 PTC heater switch power supply line 

for open circuit.

Q: Is the check result normal?

AC310631AJ

Connector: C-30 <RHD>

Harness side

AC310507

Connector C-106 
(Harness side)

BH

AC310632 AY

Connectors: C-01, C-30 <RHD>

C-01

C-30

C-01

C-30

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