Mitsubishi Evolution X. Manual - part 1283

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-83

STEP 10. Check the wiring harness between A/C 
compressor clutch relay connector A-17X (terminals 2 and 
4) and the fusible link (36).
Q: Is the wiring harness between A/C compressor clutch 

relay connector A-17X (terminals 2 and 4) and the 
fusible link (36) in good condition?
YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− How to 

Cope with Intermittent Malfunctions 

P.00-15

.

NO :  Repair the wiring harness. Check that the A/C works 

normally.

STEP 11. Check the wiring harness between A/C 
compressor clutch relay connector A-17X (terminal 3) and 
A/C compressor assembly connector B-110 (terminal 1).
Q: Is the wiring harness between A/C compressor clutch 

relay connector A-17X (terminal 3) and A/C compressor 
assembly connector B-110 (terminal 1) in good 
condition?
YES : Go to Step 12.
NO :  Repair the wiring harness. Check that the A/C works 

normally.

STEP 12. Check the wiring harness between engine 
control module connector B-10 (terminal 102) and A/C 
compressor clutch relay connector A-17X (terminal 1).
Q: Is the wiring harness between engine control module 

connector B-10 (terminal 102) and A/C compressor 
clutch relay connector A-17X (terminal 1) in good 
condition?
YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− How to 

Cope with Intermittent Malfunctions 

P.00-15

.

NO :  Repair the wiring harness. Check that the A/C works 

normally.

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-84

STEP 13. Check the refrigerant temperature switch.

CAUTION

Do not heat more than necessary.
(1) Dip the metal part of the cooling temperature switch into 

engine oil and increase the oil temperature using a gas 
burner or similar.

(2) When the oil temperature reaches the standard value, 

check that resistance is supplied between the terminals.

Standard value: 

NOTE: When the oil temperature is 155

°

C (311

°

F) or more 

and there is no continuity, the resistance will not be 2

Ω

 or 

lower until the oil temperature reduces to 125

°

C (257

°

F) or 

less.

Q: Is the refrigerant temperature switch operating 

properly?
YES : Go to Step 14.
NO :  Replace the refrigerant temperature switch. Check 

that the A/C works normally.

STEP 14. Replace the A/C-ECU.
Q: Does the A/C operate normally?

YES : No action is necessary and testing is complete.
NO :  Replace the engine control module. Check that the 

A/C works normally. 

Item

Temperature

Less than 2 ohms

Slightly below 155

° C (311° F)

No continuity

155

° C (311° F) or more

AC100787

Thermometer

Engine oil

AG

AC100810

Less than 2

Ω 

No continuity

125˚C 
(257˚F)

155˚C 
(311˚F)

OIL TEMPERATURE

AV

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-85

INSPECTION PROCEDURE 4: Blower Fan and Motor do not Turn.

Blower Motor Circuit

FUSIBLE
LINK

37

BLOWER
RELAY

ETACS-
ECU 

A/C-ECU

BLOWER
MOTOR

POWER
TRANSISTER

AC708621

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-86

.

CIRCUIT OPERATION

If the blower motor does not operate, the blower relay system is 
suspected.

.

TROUBLESHOOTING HINTS

• Malfunction of the power transistor

• Malfunction of the blower motor

• Malfunction of the A/C-ECU

• Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

STEP 1. Check blower motor connector C-115 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is blower motor connector C-115 in good condition?

YES : Go to Step 2.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.The 

blower motor should operate normally.

AC708951AP

Connectors: C-22, C-115, C-119

C-119

C-22 (B)

C-115