2000 MITSUBISHI MONTERO Service Repair Manual

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-17
DATA LIST REFERENCE TABLE
Item No.Check itemInspection contents
11Inside air temperature sensorIgnition switch: ONInside air temperature and tempera-
ture displayed on the MUT-IIare
identical.
13Outside air temperature sen-
sorIgnition switch: ONOutside air temperature and tem-
perature displayed on the MUT-II
are identical.
15Heater water temperature
sensorIgnition switch: ONHeater core surface temperature
and temperature displayed on the
MUT-IIare identical.
21Air thermo sensorIgnition switch: ONEvaporator outlet temperature and
temperature displayed on the MUT-
IIare identical.
25Photo sensorIgnition switch: ONAmount of incident light is propor-
tional to voltage displayed on the
MUT-II.
31Potentiometer for the air mix
damperIgnition switch: ON
Damper position: MAX HOTOpening angle: Approximately
100%
Ignition switch: ON
Damper position: MAX COOLOpening angle: Approximately 0%
32Potentiometer for the air
outlet changeover damperIgnition switch: ON
Damper position: FACEOpening angle: Approximately 0%
Ignition switch: ON
Damper position:FOOTOpening angle: Approximately 60%
Ignition switch: ON
Damper position: FOOT/DEFOpening angle: Approximately 80%
Ignition switch: ON
Damper position: DEFOpening angle: Approximately
100%
ACTUATOR TEST TABLE
Item No.Check itemDrive Contents
01Blower motorStopped
02Low speed
03Medium speed
04High speed
05Electric motor for the air mix damperOpening angle: Approximately 0%
06Opening angle: Approximately 50%
07Opening angle: Approximately 100%
08Electric motor for the air outlet changeoverFACE
09damperFOOT
10DEF
11Compressor ON/OFFOFF
12ON
13Inside/outside air changeover damper motorOutside air
14Inside air


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C
heck it e m C
heck co ndit io ns N
orm alco ndit io n 1 E
le ctr ic m oto r fo r th e air m ix dam per
( M AX CO OL) W
hen th e dam per fla p is m ovin g to th e
M AX CO OL posit io n. 1
0 V W
hen th e dam per fla p is m ovin g to th e
M AX HO T posit io n. F
ain t vo lt a ge (0 .5 V) 2 E
le ctr ic moto r fo r th e air outle t
c h angeove r dam per W
hen th e dam per fla p is m ovin g to th e
F A C E posit io n. 1
0 V (
F A C E) W
hen th e dam per fla p is m ovin g to th e
D EF posit io n. F
ain t vo lt a ge (0 .5 V) 3 I
n sid e/o uts id e air ch angeove r dam per
m oto r W
hen th e dam per fla p is m ovin g to th e
i n sid e air re cir c u la tio n posit io n. F
ain t vo lt a ge (0 .5 V) (
In sid e air ) W
hen th e dam per fla p is m ovin g to th e
t h e outs id e air in ductio n posit io n. 1
0 V (w hen th e moto r
i s sto pped) 4 I
n sid e/o uts id e air ch angeove r dam per
m oto r W
hen th e dam per fla p is m ovin g to th e
i n sid e air re cir c u la tio n posit io n. 1
0 V (w hen th e moto r
i s sto pped) (
O uts id e air ) W
hen th e dam per fla p is m ovin g to th e
t h e outs id e air in ductio n posit io n. F
ain t vo lt a ge (0 .5 V) 5 I
n put sig nalfr o m dualp re ssu re sw it c h D
ualp re ssu re sw it c h : O FF 0
V D
ualp re ssu re sw it c h : O N S
yste m vo lt a ge 6 M
ult i c e nte rd is p la y unit c o m munic a tio n
l in e I
g nit io n sw it c h : O N H
i: 4 -5 V
L o:0 -1 V 7 O
utp utto th e engin e-A /T -E C U W
hen th e A/C is off . 0
V o
r engin e-E C U . W
hen th e A/C is in opera tio n
( W hen co m pre sso r is opera tin g) S
yste m vo lt a ge 9 I
n putfr o m lo ck se nso r W
hen th e co m pre sso r is opera tin g 0
-0.7 5 V (p uls e
s ig nal) 1
0 O
utp ut to blo w er lin ear co ntr o lle r W
hen th e blo w er is opera tin g 0
-3.5 V (E ff e ctiv e
a lt e rn atin g vo lt a ge) 1
1 E
le ctr ic m oto r fo r th e air m ix dam per
( M AX HO T) W
hen th e dam per fla p is m ovin g to th e
M AX CO OL posit io n. F
ain t vo lt a ge (0 .5 V) W
hen th e dam per fla p is m ovin g to th e
M AX HO T posit io n. 1
0 V 1
2 E
le ctr ic moto r fo r th e air outle t
c h angeove r dam per W
hen th e dam per fla p is m ovin g to th e
F A C E posit io n. F
ain t vo lt a ge (0 .5 V) (
D EF) W
hen th e dam per fla p is m ovin g to th e
D EF posit io n. 1
0 V 1
3 E
ngin e-E C U B
lo w er sw it c h : O N
A ir outle t te m pera tu re : FO OT, FO OT/
D EF, D EF
S et te m pera tu re : M AX HO T (3 2
_C
) S
yste m vo lt a ge 1
4 B
lo w er re la y W
hen th e blo w er is sto pped S
yste m vo lt a ge W
hen th e blo w er is opera tin g 0
V

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 HEATER, AIR CONDITIONER AND VENTILATION -Troubleshooting 55B-20
TROUBLESHOOTING
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptomInspection pro-
cedure No.Reference
page
The rear A/C does not operate at all.155B-20
The rear A/C outlet air temperature can not be set.255B-21
The rear blower does not operate.355B-22
Rear blower air volume can not be changed.455B-23
Air outlet vents can not be changed in proportion to the temperature adjusting
switch.555B-23
INSPECTION PROCEDURES FOR TROUBLE SYMPTOMS
Inspection procedure 1
The rear A/C does not operate at all.
Probable cause
The rear fan switch or front rear fan switch circuit, or the power supply system
(including earth) for the rear A/C control unit may be defective. Besides that, the
rear A/C control unit may not be operating correctly due to a defective harness
(such as short circuit).DMalfunction of the rear fan switch
DMalfunction of the front rear fan switch
DMalfunction of harness or connector
DMalfunction of the rear A/C control unit
NG
Repair
NG
Check the harness wire between the ignition switch (IG2) and
the rear A/C control unit, and repair if necessary.
NG
Repair
NG
Check the harness wire between the rear A/C control unit and
body earth, and repair if necessary.
OK
Replace the rear A/C
control unit.
NG
Repair
NG
Repair
NG
Check the harness wires between the rear A/C switch and the
front rear fan switch, between the front rear fan switch and
the rear A/C control unit, and repair if necessary.
OK
Check the trouble symptoms.
Check an abnormal circuit by measuring voltage at the rear
A/C control unit terminals.
OK
Check at the rear A/C control unit terminals
(Refer to GROUP 55A - Rear Heater/Rear Cooler).
Check the following connectors:E-23, E-109, E-14, D-123,
D-214,E-119
(3) NGOK
Check the trouble symptoms.
Check the following connectors:E-23, D-30(2) NG
OK
Check the trouble symptoms.
OK
Measure at rear A/C control unit connector E-23.
DDisconnect the connector and measure at the harness
side.
DIgnition switch: ON
(1) Voltage between terminal 5 and body earth
OK:System voltage
(2) Continuity between terminal 2 and body earth
OK:Continuity
(3) Voltage between terminal 13 and body earth
OK:System voltage (rear fan switch or front rear fan
switch: OFF), 0 V (rear fan switch or front rear fan
switch: ON)(1) NGCheck the following connectors:E-23, D-32, D-210, D-208
OK
Check the front rear fan switch
(Refer to GROUP 55A - Rear Heater/Rear Cooler).NG
Replace
Check the rear A/C switch (rear fan switch).
(Refer to GROUP 55A - Rear Heater/Rear Cooler.)NG
Replace


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