Mitsubishi Eclipse. Manual - part 651

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-7

AC102871 AB

<3.0L ENGINE>

AC102598

CONNECTORS: A-09X, A-18X

A-18X

A-09X

AB

AC101134

BATTERY

FUSIBLE LINK (2)

AG

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-8

.

CIRCUIT OPERATION

• The fan controller is powered from fusible link 

number 2.

• The ECM <M/T> or PCM <A/T> judges the 

required revolution speed of radiator fan motor 
and condenser fan motor using the input signals 
transmitted from A/C switch, automatic compres-
sor controller, vehicle speed sensor and engine 
coolant temperature sensor. The ECM <M/T> or 
PCM <A/T> activates the fan controller to drive 
the radiator fan motor and condenser fan motor.

.

TECHNICAL DESCRIPTION

• The cause could be a malfunction of the fan con-

troller power supply or ground circuit.

• The cause could also be a malfunction of the fan 

controller or the ECM <M/T> or PCM <A/T>.

.

TROUBLESHOOTING HINTS

• Malfunction of fusible link

• Malfunction of fan control relay

• Malfunction of fan controller

• Malfunction of ECM <M/T> or PCM <A/T>

• Damaged wiring harness or connector

.

DIAGNOSIS

Required Special Tool:

• MB991223: Harness Set

STEP 1. Check the circuit at fan controller connector A-30 
(terminal number 3).
(1) Disconnect fan controller connector A-30 (terminal number 

3), and measure at the harness side connector.

(2) Measure the voltage between terminal number 3 and 

ground.

• When the ignition switch is turned to "ON" position, volt-

age should be battery positive voltage.

Q: Is the voltage battery positive voltage when the ignition 

switch is turned to "ON" position?
YES : Go to Step 7.
NO :  Go to Step 2.

AC000244

CONNECTOR: C-07

AC

AC000260AD

CONNECTORS: A-30, A-30-1

A-30-1

A-30

RADIATOR
FAN

AC000245 AE

CONNECTOR: 
       C-49 <2.4L-M/T>, C-50 <2.4L-A/T>
       C-51 <3.0L-M/T>, C-52 <3.0L-A/T>

ECM <M/T>
OR
PCM <A/T>

AC000246

CONNECTOR A-30

AB

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-9

STEP 2. Check the fan control relay.
Refer to 

P.14-20

.

Q: Is the fan control relay in good condition?

YES : Go to Step 3.
NO :  Replace it, then go to Step 10.

STEP 3. Check for continuity between fusible link number 
2 and fan control relay connector A-09X (terminal number 
4).
Q: Are the harness wires between fusible link number 2 

and fan control relay connector A-09X (terminal number 
4) damaged? 
YES : Repair or replace them, then go to Step 12.
NO :  Go to Step 4.

AC102598

CONNECTOR: A-09X

A-09X

AC

AC101134

BATTERY

FUSIBLE LINK (2)

AG

ENGINE COOLING DIAGNOSIS

TSB Revision

COOLING SYSTEM

14-10

STEP 4. Check for continuity between fan control relay 
connector A-09X (terminal number 2) and fan controller 
connector A-30 (terminal number 3).
Q: Are the harness wires between fan control relay 

connector A-09X (terminal number 2) and fan controller 
connector A-30 (terminal number 3) damaged?
YES : Repair or replace them, then go to Step 12.
NO :  Go to Step 5.

STEP 5. Check for continuity between MFI relay connector 
A-18X (terminal number 4) and fan control relay connector 
A-09X (terminal number 1).
Q: Are the harness wires between MFI relay connector 

A-18X (terminal number 4) and fan control relay 
connector A-09X (terminal number 1) damaged?
YES : Repair or replace them, then go to Step 12.
NO :  Go to Step 6.

STEP 6. Check for continuity between fan control relay 
connector A-09X (terminal number 3) and ground.
Q: Are the harness wires between fan control relay 

connector A-09X (terminal number 3) and ground 
damaged?
YES : Repair or replace them, then go to Step 12.
NO :  Go to Step 7.

AC102598

CONNECTOR: A-09X

A-09X

AC

AC000270 AB

CONNECTOR: A-30

RADIATOR
FAN

AC102598

CONNECTORS: A-09X, A-18X

A-18X

A-09X

AB

AC102598

CONNECTOR: A-09X

A-09X

AC