Page 441 of 558

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-51
NG
Repair OK
Check the trouble symptom.
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the condenser fan motor relay (HI)
and the engine-ECU, and repair if necessary.
Measure at the radiator fan motor relay (HI) connector A-114X.
Disconnect the connector.
(1) Continuity between 4-B-59 and connector terminal (20)
OK:Continuity
(2) Voltage between terminal (2) and body earth (Ignition
switch: ON)
OK:System voltage
(3) Voltage between terminal (1) and body earth
OK:System voltage(1) NGCheck the following connectors:
A-114X, A-28, B-59
From the previous page
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the condenser fan motor relay (HI)
and the ignition switch, and repair if necessary.
(2) NG
Check the following connector:
A-114X
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the condenser fan motor relay (HI)
and the fusible link 2, and repair if necessary.
(3) NG
Check the following connector:
A-114X
OK
Measure at the condenser fan motor connector A-99.
Disconnect the connector, and measure at the harness
side connector.
Connect the terminal B-59 to the earth.
Voltage between terminal (1) and body earth (Ignition switch:
ON)
OK:System voltageNOCheck the following connector:
A-112X
NG
Check the harness between the condenser fan motor relay (HI)
and the condenser fan motor, and repair if necessary.
Inspection procedure 14
Rear defogger does not operate.
Probable cause
If the rear defogger does not operate when the rear defogger switch is turned
on (timer operates for 20 minutes), the cause is probably a malfunction of the
A/C-ECU power supply system (earth).Malfunction of connector or harness
Malfunction of A/C-ECU
Can an operating sound be heard when the rear defogger switch
is operated?NOInspection procedure 15 (Refer to P.55-52.)
YES
Replace the A/C-ECU.
Page 442 of 558

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-52
Inspection procedure 15
A/C-ECU power supply circuit check
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the fusible link
No.1, and repair if necessary.
OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the junction block,
and repair if necessary.
OK
Check the following connector:
B-05NG
Repair
OK
Check the trouble symptom.NGReplace the A/C-ECU.
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the body earth,
and repair if necessary.
NG
Repair
OK
Measure at the A/C-ECU connector B-05.
Disconnect the connector, and measure at the harness
side connector.
Continuity between terminal (29) and body earth
OK:Continuity
Continuity between terminal (35) and body earth
OK:ContinuityNGCheck the following connectors:
B-05, B-48, B-19, B-69, B-80
OK
Measure at the A/C-ECU connector B-05.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (28) and body earth (Ignition
switch: ON)
OK:System voltageNGCheck the following connectors:
B-49, B-75, B-76
Measure at the A/C-ECU connector B-04.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (3) and body earth
OK:System voltageNGCheck the following connectors:
B-49, B-75, B-73
Page 443 of 558

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-53
Inspection procedure 16
A/C compressor control circuit check
Measure at the A/C-ECU connector B-05.
Blower switch and A/C switch: ON
Setting temperature: 17C
Connect the connector.
Voltage between terminal (34) and body earth (Ignition
switch: ON)
OK:System voltageNGCheck the following connector:
B-05
NG
Repair OK
Check the trouble symptom.
NG
Replace the A/C-ECU.
OK
Measure at the A/C compressor relay connector A-116X.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (2) and body earth
OK:System voltageNGCheck the following connectors:
A-49, B-15, B-05
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the A/C-ECU and the A/C compressor
relay, and repair if necessary.
OK
Measure at the engine-ECU connector B-54 or B-59.
Disconnect the connector, and measure at the harness
side connector.
Voltage between terminal (21) or (22) and body earth
OK:System voltageNGCheck the following connectors:
A-28, A-116X
NG
Repair OK
Check the trouble symptom.
NG
Check the harness between the A/C compressor relay and the
engine-ECU, and repair if necessary.
OK
Replace the engine-ECU.
Page 444 of 558

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-54
DATA LIST REFERENCE TABLE
Check itemCheck conditionNormal condition
Inside air temperature sensor
MUT-II (11)Ignition switch: ONInside air temperature and temper-
ature displayed on the MUT-II are
identical.
Outside air temperature sen-
sor
MUT-II (13)Ignition switch: ONOutside air temperature and tem-
perature displayed on the MUT-II
are identical.
Heater water temperature
sensor
MUT-II (15)Ignition switch: ONHeater core surface temperature
and temperature displayed on the
MUT-II are identical.
Air thermo sensor
MUT-II (21)Ignition switch: ONEvaporator surface temperature
and temperature displayed on the
MUT-II are identical.
Photo sensor
MUT-II (25)Ignition switch: ONAmount of incident light is propor-
tional to voltage displayed on the
MUT-II.
Air mix damper potentiometer
MUTII(31)
Ignition switch: ONDamper positionOpening degree (%)
MUT-II (31)MAX. HOTApprox. 100
MAX. COOLApprox. 0
Air outlet changeover damper
potentiometer
Ignition switch: ONDamper positionOpening degree (%)
potentiometer
MUT-II (32)FACEApprox. 0
FOOTApprox. 50
FOOT/DEF.Approx. 75
DEF.Approx. 100
CHECK AT THE A/C-ECU TERMINALS
A/C-ECU
The parenthesized values in “Normal condition” column are for your reference.
Terminal
No.
Check itemCheck conditionNormal condition
1Front power transistor collector outputWhen blower switch is at OFFSystem voltage
When blower switch is at LOApprox. 7 V
When blower switch is at HIAlmost no voltage (0 V)
2Front power transistor base outputWhen blower switch is at OFF0 V
When blower switch is at LOApprox. 1.3 V
When blower switch is at HIApprox. 2.5 V
3BackupAt all timesSystem voltage
Page 445 of 558

FULL-AUTOMATIC AIR CONDITIONER – Troubleshooting55-55
Terminal
No.Normal condition Check condition Check item
4Heater water temperature sensor
inputWhen sensor section temperature is
25C (4 kΩ)2.3 – 2.9 V
5Air mix damper potentiometer inputWhen damper is moved to MAX. HOT
position4.7 – 5.0 V
6Air outlet changeover damper poten-
tiometer inputWhen damper is moved to DEF.
position4.8 – 5.2 V
7Outside air temperature sensor inputWhen sensor section temperature is
25C (4 kΩ)2.3 – 2.9 V
8Air thermo sensor inputWhen sensor section temperature is
25C (4 kΩ)2.3 – 2.9 V
9Photo sensor (–)At luminous intensity of 0 lux0 V
At luminous intensity of 100,000 lux or
more–0.1 – 0.2 V
10Sensor power supplyAt all times4.8 – 5.2 V
12Blower motor HI relay (Exciting circuit)When blower switch is in HI1.5 V or less
When blower switch is in a position
other than HISystem voltage
16Rear defoggerWhen rear defogger switch is ON1.5 V or less
When rear defogger switch is OFFSystem voltage
17Diagnosis date outputWhen ignition switch is ON0 V ↔ 12 V
18Diagnosis control outputWhen ignition switch is ONSystem voltage – 2 V
19Photo sensor (+)At all times0 V
20Sensor earthAt all times0 V
21Air outlet changeover damper motor
(FACE)When damper is moved to FACE
position10 V
When damper is moved to DEF.
positionAlmost no voltage
(0.5 V)
22Air mix damper motor (MAX. COOL)When damper is moved to MAX.
COOL position10 V
When damper is moved to MAX. HOT
positionAlmost no voltage
(0.5 V)
23Inside/outside air changeover damper
motor (Inside)When switch is set to inside air
positionAlmost no voltage
(0.5 V)
When switch is set to outside air
position10 V
24Air outlet changeover damper motor
(DEF.)When damper is moved to FACE
positionAlmost no voltage
(0.5 V)
When damper is moved to DEF.
position10 V
Page 446 of 558
FULL-AUTOMATIC AIR CONDITIONER –
Troubleshooting /
On-vehicle Service55-56
Terminal
No.Normal condition Check condition Check item
25Air mix damper motor (MAX. HOT)When damper is moved to MAX.
COOL positionAlmost no voltage
(0.5 V)
When damper is moved to MAX. HOT
position10 V
26Inside/outside air changeover damper
motor (Outside)When switch is set to inside air
position10 V
When switch is set to outside air
positionAlmost no voltage
(0.5 V)
28IG2 power supplyWhen ignition switch is ONSystem voltage
29EarthAt all timesContinuity
30ILL power supplyWhen lighting switch is at ONSystem voltage
34A/C outputWhen A/C is OFF0 V
When A/C is ONSystem voltage
35EarthAt all timesContinuity
ON-VEHICLE SERVICE
REFRIGERANT CHARGING, LEVEL CHECK,
ADDITION AND REMOVAL, PERFORMANCE
TEST, DUAL PRESSURE SWITCH SIMPLE
CHECK
Follow the same procedures as for the heater and manual
air conditioner. (Refer to P.55-6.)
Page 447 of 558
FULL-AUTOMATIC AIR CONDITIONER – On-vehicle Service55-57
POWER RELAY CHECK
Follow the same procedures as for the heater and manual
air conditioner except for the following. (Refer to P.55-13.)
BLOWER HIGH SPEED RELAY
Battery voltageTerminal No.
1234
Power is not supplied
Power is supplied
IDLE-UP OPERATION CHECK
The idle-up inspection procedures are the same as for the
heater and manual air conditioner. (Refer to P.55-14.)
Standard value: 750 ± 50 r/min
Standard value: 850 ± 50 r/min
NOTE
If the idling speed is not within the standard value range,
adjust it.
Blower high speed relay
Page 448 of 558
FULL-AUTOMATIC AIR CONDITIONER –
Damper Control Motor Assembly
and Power Transistor55-58
DAMPER CONTROL MOTOR ASSEMBLY AND POWER
TRANSISTOR
REMOVAL AND INSTALLATION
1
23
4
5 6
7
Inside/outside air changeover
damper motor removal steps
Glove box, glove box frame
1. Linkage connection
2. Inside/outside air changeover
damper motor
Air outlet port changeover damper
motor removal steps
Instrument lower panel
3. Linkage connection
4. Air outlet port changeover damper
motorAir mix damper motor removal
steps
Front floor console, console side cover
5. Linkage connection
6. Air mix damper motor
Power transistor removal steps
Glove box, glove box frame
7. Power transistor