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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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-21
Inspection procedure 2
The rear A/C outlet air temperature can not be set.
Probable cause
If the air outlet temperature can not be changed after a temperature control
switch is operated,the temperature control switch, the air thermo sensor, the
magnet valve or the air mix damper maybe defective.DMalfunction of the rear A/C switch
DMalfunction of the air thermo sensor
DMagnet valve
DMalfunction of the electric motor for the air mix
damper
DMalfunction of harness or connector
DMalfunction of the rear A/C control unit
Repair
NG
NG
Check the harness wire between the rear A/C control unit and
the rear A/C switch, and repair if necessary.
NG
RepairNG
Check the harness wire between the rear A/C control unit and
the air thermo sensor, and repair if necessary.
NG
Repair
NG
Check the harness wire between the rear A/C control unit and
the air mix damper motor, and repair if necessary.
OK
Replace the rear A/C control unit.NG
Repair
NG
Check the harness wire between the rear A/C control unit and
the magnet valve, and repair if necessary.
OK
Check the trouble symptoms.
Check the following connectors:E-23, D-123, G-26,
G-24-1, G-24-4
(6) NG
OK
Check the trouble symptoms.
Check the following connectors:E-23, D-123, G-24,
G-24-1, G-24-2(3 - 5) NG
OK
Check the trouble symptoms.
Check the following connectors:E-23, D-123, G-26,
G-24-1, G-24-3(2) NG
OK
Check the trouble symptoms.
OK
Measure at rear A/C control unit connector E-23.
DConnect the connector.
DIgnition switch: ON
(1) Voltage between terminal 3 and body earth
OK:1 V (Temperature control switch: MAX HOT),
4 V (Temperature control switch: MAX COOL)
(2) Voltage between terminal 12 and body earth
OK:2.2 V [Air thermo sensor temperature: 25
_C
(1.5 k
W)]
(3) Voltage between terminal 7 and body earth
OK:1 V (Air mix damper: MAX HOT),
4 V (Air mix damper: MAX COOL)
(4) Voltage between terminal 6 and body earth
OK:10 V (When the air mix damper flap is moving to the
MAX COOL position), 0.5 V (When the air mix
damper flap is moving to the MAX HOT position)
(5) Voltage between terminal 14 and body earth
OK:0.5 V (When the air mix damper flap is moving to
the MAX COOL position), 10 V (When the air mix
damper flap is moving to the MAX HOT position)
(6) Voltage between terminal 1 and body earth
OK:System voltage (magnetic valve: OFF), 0.5 V (mag-
netic valve: ON)(1) NGCheck the following connectors:E-23, D-123, E-119
OK
Check the magnetic valve.
(Refer to GROUP 55A - Rear Heater/Rear Cooler.)NG
Replace
OK
Check the air mix damper motor.
(Refer to GROUP 55A - Rear Heater/Rear Cooler.)NG
Replace
OK
Check the air thermo sensor.
(Refer to GROUP 55A - Rear Heater/Rear Cooler.)NG
Replace
Check the rear A/C switch (temperature control switch).
(Refer to GROUP 55A - Rear Heater/Rear Cooler.)NG
Replace
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