Mitsubishi L200. Manual - part 878

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-41

Inspection Procedure 3: The blower air volume cannot be changed

Blower Motor Circuit

FUSIBLE
LINK

20

IGNITION
SWITCH (IG2)

BLOWER
RELAY

A/C-ECU

BLOWER
MOTOR

POWER
TRANSISTER

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

AC805774 AB

COMMENTS ON TROUBLE SYMPTOM
If the blower air amount cannot be changed when the 
blower switch is operated, the blower switch may be 
defective.

TROUBLESHOOTING HINTS

• Malfunction of the resistor

• Damaged the wiring harness or connectors

• Malfunction of the automatic A/C control panel (A/

C-ECU)

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-42

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-46 power transistor 
connector

AC509611CG

Connector: C-46 <LHD>

Harness side

AC509932CN

Harness side

Connector: C-46 <RHD>

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the connector. 

STEP 2. Check the wiring harness between C-28 
blower motor connector terminal No.2 and C-46 
power transistor connector terminal No.1.

AC509613

Connector: C-28 <LHD>

BU

Harness side

AC509930BU

Connector: C-28 <RHD>

Harness side

AC509611CG

Connector: C-46 <LHD>

Harness side

AC509932CN

Harness side

Connector: C-46 <RHD>

• Check the blower relay earth wires for open cir-

cuit.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the wiring harness.

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-43

STEP 3. Connector check: C-44 A/C-ECU 
connector

AC509611CH

Connector: C-44 <LHD>

Harness side

AC509932CO

Connector: C-44 <RHD>

Harness side

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the connector. 

STEP 4. Check the wiring harness between C-46 
power transistor connector (terminals 1 and 3) 
and C-44 A/C-ECU connector (terminals 36 and 
35).

AC509611 CK

Connectors: C-44,C-46 <LHD>

C-44 Harness side

C-46Harness side

C-44

C-46

AC509932CT

Connectors: C-44, C-46 <RHD>

C-44 
Harness side

C-46 Harness side

C-44 C-46

C-44 Harness side

• Check the A/C-ECU input line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the wiring harness.

TROUBLESHOOTING

AUTOMATIC AIR CONDITIONER

55B-44

STEP 5. Resistance measurement at the C-46 
power transistor connector.

AC509611CG

Connector: C-46 <LHD>

Harness side

AC509932CN

Harness side

Connector: C-46 <RHD>

(1) Disconnect the connector, and measure at the 

wiring harness side.

AC310506IB

Connector C-46 
(Harness side)

(2) Measure the resistance between terminal 2 and 

body earth.

OK: Continuity (Less than 2

Ω)

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 6.

STEP 6. Check the wiring harness between C-46 
power transistor connector terminal No.2 and 
body earth.

AC509611CG

Connector: C-46 <LHD>

Harness side

AC509932CN

Harness side

Connector: C-46 <RHD>

• Check the power transistor earth line for open cir-

cuit.

Q: Is the check result normal?

YES : 

The trouble can be an intermittent 

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

NO : 

Repair the wiring harness.

STEP 7. Replace the power transistor, and then 
recheck the trouble symptom
 Check that the blower motor works normally.

Q: Is the check result normal?

YES : 

This diagnosis is complete.

NO : 

Replace the A/C-ECU.