Mitsubishi Lancer (4A9 engine). Manual - part 283
TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION
55A-13
DIAGNOSIS PROCEDURE
STEP 1. Connector check: C-59 heater control
unit connector and C-118 fin thermo sensor
connector
Q: Is the check result normal?
YES :
Go to Step 2.
NO :
Repair the connector.
STEP 2. Check the wiring harness between C-59
heater control unit connector (terminals 21 and
22) and C-118 fin thermo sensor connector
(terminals 2 and 1).
• Check the sensor signal line and earth line for
open or short circuit.
Q: Is the check result normal?
YES :
Go to Step 3.
NO :
Repair the wiring harness.
STEP 3. Check the fin thermo sensor.
Refer to .
Q: Is the check result normal?
YES :
Go to Step 4.
NO :
Replace the fin thermo sensor.
STEP 4. Check whether the diagnosis code is
reset.
Q: Is the diagnosis code set?
YES :
Replace the heater control unit.
NO :
The trouble can be an intermittent
malfunction (Refer to GROUP 00, How to
Cope with Intermittent Malfunction ).
Code No.B1031: Fin thermo Sensor system (short circuit) <Vehicles with A/C>
Code No.B1032: Fin thermo Sensor system (open circuit) <Vehicles with A/C>
Fin Thermo Sensor Circuit
FIN THERMO
SENSOR
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 : Grey R : Red P : Pink V : Violet PU : Purple SI : Silver
AC612706
Connectors: C-13, C-118 <LHD>
AD
C-13 (B)
C-118
AC612710
Connectors: C-13, C-118 <RHD>
AR
C-118
C-13 (B)
COMMENTS ON TROUBLE SYMPTOM
This code is set when the fin thermo sensor circuit is
short (Code No.B1031) or is open (Code No.B1032).