2000 MITSUBISHI MONTERO relay

HEATER, AIR CONDITIONER AND VENTILATION - Troubleshooting55A-7
TROUBLESHOOTING
Trouble symp-
tomProbable causesRemedyRefer-
ence
page
The rear cool-Malfunction of fuseReplace the fuse.–
er does notMalfunction of harness or connectorRepair the harness or connector.–operate.
Refrigerant leak or overfilling of refrigerantReplenish the refrigerant, repair the leak
or take out some of the refrigerant.–
Malfunction of the rear A/C switchReplace the rear A/C switch.55A-32
Malfunction of the front rear fan switchReplace the front rear fan switch.55A-33
Malfunction of the air thermo sensorReplace the air thermo sensor.55A-39
Malfunction of the rear blower relayReplace the rear blower relay.55A-18
The rear blower motor is defective.Replace the rear blower motor.55A-40
The rear cooler control unit is defective.Replace the rear cooler control unit.55A-34
When the rear
cooler is oper-
ating, temper-
ature inside
the passenger
compartment
does not de-
crease(cool air
is not emitted).Refrigerant leakReplenish the refrigerant and repair the
leak.–
When the rear
heater is oper-
ating, temper-
ature inside
the passenger
compartment
does not in-
crease(warm
air is not
emitted).Malfunction of the air thermo sensorReplace the air thermo sensor.55A-39
The blowerMalfunction of fuseReplace the fuse.–
motor does notMalfunction of harness or connectorRepair the harness or connector.–run.
Malfunction of the rear blower relayReplace the blower relay.55A-18
The rear blower motor is defective.Replace the blower motor.55A-40
Malfunction of the rear A/C switchReplace the rear A/C switch.55A-32
Malfunction of the front rear fan switchReplace the front rear fan switch.55A-33
Malfunction of the resistorReplace the resistor.55A-35
The rear cooler control unit is defective.Replace the rear cooler control unit.55A-34
The blowerMalfunction of fuseReplace the fuse.–
motor does notMalfunction of harness or connectorRepair the harness or connector.–stop running.
Malfunction of the rear A/C switchReplace the rear A/C switch.55A-32
Malfunction of the front rear fan switchReplace the front rear fan switch.55A-33
Malfunction of the resistorReplace the resistor.55A-35
The rear cooler control unit is defective.Replace the rear cooler control unit.55A-34


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HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-11
Inspection procedure 5
The blower does not operate.
Probable cause
If no air comes out of the blower even though the blower switch is on, the
cause is probably a malfunction of the front blower relay circuit.DMalfunction of the front blower relay
DMalfunction of the blower linear controller
DMalfunction of the blower motor
DMalfunction of harness or connector
DMalfunction of the A/C-ECU
NG
Repair
NG
Repair
NG
Repair
NG
Check the harness wire between the front blower relay and
the ignition switch (IG2), and repair if necessary.
NG
Check the harness wire between the front blower relay and
the battery, and repair if necessary.
NG
Repair
NG
Check the harness wire between the blower linear controller
and body earth, and repair if necessary.
OK
Replace the automatic A/C control panelassembly (A/C-ECU).
NG
Check the harness wires between the front blower relay and
the blower linear controller, between the front blower relay and
the blower motor, between the blower motor and the blower
linear controller and between the front blower relay and the
A/C-ECU.NG
Repair
OK
Check the trouble symptoms.
OK
Check the following connectors:D-220, D-208, D-126, D-17,
D-131,D-209
OK
Check the trouble symptoms.
OK
Measure at blower linear controller connector D-126.
DDisconnect the connector and measure at the harness
side.
DContinuity between terminal 4 and body earth
OK:ContinuityNGCheck the following connector:D-126
OK
Check the trouble symptoms.
Check the following connectors:D-220, D-208
(2) NG
OK
Check the trouble symptoms.
NG
Measure at front blower relay connector D-220.
DDisconnect the connector, and measure at the J/B side.
DIgnition switch: ON
(1) Voltage between terminal 2 and body earth
OK:System voltage
(2) Voltage between terminal 3 and body earth
OK:System voltage(1) NGCheck the following connectors:D-220, D-211, D-27
OK
Check the blower linear controller (Refer to P.55B-26).NG
Replace
OK
Check the blower motor (Refer to GROUP 55A - Front A/C).NG
Replace
OK
Check the front blower relay
(Refer to GROUP 55A - On-vehicle Service).NG
Replace
MUT-
IIActuator Test
01, 02, 03, 04 Blower motorOKReplace the automatic A/C control panelassembly (A/C-ECU).


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HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-14
Inspection procedure 9
The rear defogger does not operate.
Probable cause
When the rear defogger does not operate even if the rear defogger switch is on
(the defogger remains on for twenty minutes due to a timer function), the rear
defogger relay system may be defective.DMalfunction of the defogger relay
DMalfunction of harness or connector
DMalfunction of the A/C-ECU
NG
Repair
NG
Check the harness wire between the defogger and body earth,
and repair if necessary.
NG
Repair
NG
Repair
OK
Replace the automatic A/C control panelassembly (A/C-ECU).
NG
Check the harness wire between the defogger relay and the
battery, and repair if necessary.
NG
Repair
NG
Check the harness wires between the defogger relay and the
defogger and between the defogger relay and the A/C-ECU.NG
Repair
OK
Check the trouble symptoms.
OK
Check the following connectors:D-217, D-218, D-124 drive vehicles>, G-06, I-03, D-131
OK
Check the trouble symptoms.
OK
Measure at defogger connector I-01.
DDisconnect the connector and measure at the harness
side.
DContinuity between terminal 1 and body earth
OK:ContinuityNGCheck the following connector:I-01
OK
Check the trouble symptoms.
Check the following connectors:D-217, D-211, D-27
(2) NGNG
Check the harness wire between the defogger relay and the
ignition switch (IG2), and repair if necessary.
OK
Check the trouble symptoms.
OK
Measure at defogger relay connector D-217.
DDisconnect the connector, and measure at the J/B side.
DIgnition switch: ON
(1) Voltage between terminal 1 and body earth
OK:System voltage
(2) Voltage between terminal 2 and body earth
OK:System voltage(1) NGCheck the following connectors:D-217, D-208
Check the defogger relay (Refer to GROUP 54A – Defogger).NG
Replace


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HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-15
Inspection procedure 10
The condenser fan does not operate .
Probable cause
If the condenser fan does not operate, the condenser fan relay or motor may be
defective.DMalfunction of the condenser fan relay
DMalfunction of harness or connector
DMalfunction of the engine-A/T-ECU or
engine-ECU
NG
Check the harness wire between the condenser fan relay and
the ignition switch (IG2), and repair if necessary.
NG
Repair
NG
Check the harness wire between the condenser fan motor and
body earth, and repair if necessary.
NG
Repair
NG
Repair
OK
Replace the engine-A/T-ECU or engine-ECU
.
NG
Check the harness wire between the condenser fan relay and
fusible link (1), and repair if necessary.
NG
Repair
NG
Check the harness wires between the condenser fan relay
and the condenser fan motor, between the condenser fan
relay and the engine-A/T-ECU or the
engine-ECU.NG
Repair
OK
Check the trouble symptoms.
OK
Check the following connectors:A-10X, A-27,A-04 drive vehicles>, D-143, D-116,
D-119, D-110<4M41>
OK
Check the trouble symptoms.
OK
Measure at condenser fan motor connector A-27.
DDisconnect the connector and measure at the harness
side.
DContinuity between terminal 2 and body earth
OK:ContinuityNGCheck the following connector:A-27
OK
Check the trouble symptoms.
Check the following connector:A-10X
(2) NG
OK
Check the trouble symptoms.
OK
Measure at condenser fan relay connector A-10X.
DDisconnect the connector, and measure at the J/B side.
DIgnition switch: ON
(1) Voltage between terminal 3 and body earth
OK:System voltage
(2) Voltage between terminal 5 and body earth
OK:System voltage(1) NGCheck the following connectors:A-10X, A-15, D-27, D-210,
D-208
OK
Check the condenser fan motor
(Refer to GROUP 55A - Condenser Fan).NG
Replace
Check the condenser fan relay
(Refer to GROUP 55A - On-vehicle Service).NG
Replace


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HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-16
Inspection procedure 11
The condenser fan does not operate <4D56>.
Probable cause
If the condenser fan does not operate, the condenser fan relay or motor may be
defective.DMalfunction of the condenser fan relay
DMalfunction of harness or connector
DMalfunction of the engine-A/T-ECU or
engine-ECU
NG
Check the harness wire between the condenser fan relay and
the ignition switch (IG2), and repair if necessary.
NG
Repair
NG
Check the harness wire between the condenser fan motor and
body earth, and repair if necessary.
NG
Repair
NG
Repair
OK
NG
Check the harness wire between the condenser fan relay and
fusible link (1), and repair if necessary.
NG
Repair
NG
Check the harness wires between the condenser fan relay
and the condenser fan motor and between the condenser fan
relay and theengine coolant temperaturesensor, and repair if
necessary.
OK
Check the trouble symptoms.
OK
Check the following connectors:A-10X, A-27, A-04 drive vehicles>, D-143, B-47
OK
Check the trouble symptoms.
OK
Measure at condenser fan motor connector A-27.
DDisconnect the connector and measure at the harness
side.
DContinuity between terminal 2 and body earth
OK:ContinuityNGCheck the following connector:A-27
OK
Check the trouble symptoms.
Check the following connector:A-10X
(2) NG
OK
Check the trouble symptoms.
OK
Measure at condenser fan relay connector A-10X.
DDisconnect the connector, and measure at the J/B side.
DIgnition switch: ON
(1) Voltage between terminal 3 and body earth
OK:System voltage
(2) Voltage between terminal 5 and body earth
OK:System voltage(1) NGCheck the following connectors:A-10X, A-15, D-27, D-210,
D-208
OK
Check the condenser fan motor
(Refer to GROUP 55A - Condenser Fan).NG
Replace
Check the condenser fan relay
(Refer to GROUP 55A - On-vehicle Service).NG
Replace
NG
ReplaceReplace the engine coolant temperaturesensor.


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HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-19
Termi-
nal No.Normal condition Check conditions Check item
15Rear defoggerRear defogger: OFFSystem voltage
Rear defogger: ON1.5 V or less
16Multi center display unit communication
lineIgnition switch: ONHi: 4 - 5 V
Lo: 0 - 1 V
17Multi center display unit communication
lineIgnition switch: ONHi: 4 - 5 V
Lo: 0 - 1 V
18Multi center display unit communication
line shieldAt all times0V
19Diagnosis outputIgnition switch: ONA voltmeter needle
fluctuates between 0
and 12 V.
20Input from A/C compressor relayWhen the A/C is off.0V
When the A/C is in operation
(When compressor is operating)System voltage
21Power supply to potentiometerAt all times5V
22Input from outside air temperature
sensorSensor temperature: 25
_C (1.7 kW)1.9 V
23Input from heater water temperature
sensorSensor temperature: 25
_C(5kW)2.8 V
24Input from potentiometer for air mix
damperWhen the damper flap is moving to the
MAX HOT position.0.7 - 1.3 V
25Power supply to illuminationLighting switch: ONSystem voltage
26Power supply to ignition switch (IG2)Ignition switch: ONSystem voltage
27Power supply to ignition switch (ACC)Ignition switch: ACCSystem voltage
28Backup power supplyAt all timesSystem voltage
29Earth to sensor and potentiometerAt all times0V
30Input from air thermo sensorSensor temperature: 25
_C (1.5 kW)2.2 V
31Photo sensor (+)During 800 kcal/m2-h1V
32Input from potentiometer for the air
outlet changeover damperWhen the damper flap is moving to the
DEF position.0.7 - 1.3 V
33Diagnosis inputIgnition switch: ON0V
34Compressor lock signal (ignition signal)Engine speed: 3 000 r/min0.3 - 3.0
35Illumination earthAt all timesContinuity
36EarthAt all timesContinuity
CHECK AT ENGINE-A/T-ECU OR ENGINE-ECU TERMINALS
Refer to GROUP 13A – Troubleshooting or GROUP 13B – Troubleshooting .


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HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-22
Inspection procedure 3
The rear blower does not operate.
Probable cause
If no air comes out of the air vents even if the rear fan switch or the front rear
fan switch is turned on, the rear blower relay circuit may be defective.DMalfunction of the rear blower relay
DMalfunction of the blower motor
DMalfunction of the rear A/C switch
DMalfunction of harness or connector
OK
Replace the rear A/C control unit.
OK
NG
Repair
NG
Repair
NG
Check the harness wire between the rear blower relay and
the ignition switch (IG2), and repair if necessary.
NG
Repair
NG
Check the harness wire between the rear blower relay and
fusible link (2), and repair if necessary.
NG
Repair
NG
Check the harness wires between the rear blower relay and
the rear A/C switch and between the rear blower relay and
the front rear fan switch, and repair if necessary.
NG
Repair
NG
Check the harness wire between the blower motor and the
rear A/C switch and between the rear A/C switch and body
earth, and repair if necessary.
NG
Repair
OK
Check the trouble symptoms.
OK
Check the following connectors:D-214, D-123, G-22,
G-22-1
OK
Check the trouble symptoms.
OK
Measure at blower motor connector G-22-1.
DDisconnect the connector and measure at the harness
side.
DAir volume adjusting switch: 3
DContinuity between terminal 1 and body earth
OK:ContinuityNGCheck the following connectors:G-22-1, G-22, E-119
OK
Check the trouble symptoms.
Check the following connectors:D-214, D-123, E-119,
E-109, E-14
(3) NG
OK
Check the trouble symptoms.
Check the following connectors:D-214, D-27(2) NG
OK
Check the trouble symptoms.
OK
Measure at rear blower relay connector D-214.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
(1) Voltage between terminal 1 and body earth
OK:System voltage
(2) Voltage between terminal 5 and body earth
OK:System voltage
(3) Voltage between terminal 3 and body earth
OK:0 V (Rear fan switch or front rear fan switch: ON)(1) NGCheck the following connectors:D-214, D-32, D-210, D-208
OK
Check the rear A/C switch (air volume adjusting switch)
(Refer to GROUP 55A - Rear Heater/Rear Cooler).NG
Replace
OK
Check the blower motor
(Refer to GROUP 55A - Rear Heater/Rear Cooler).NG
Replace
Check the rear blower relay
(Refer to GROUP 55A - On-vehicle Service).NG
Replace
Check the harness wire between the blower motor and the
rear blower relay.


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