1991 MITSUBISHI 3000GT air condition

FULL AUTO AIR CONDITIONER - Troubleshootina55-43
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JO
6
-
7
s
s
-
IO
-
Symptom
Inside/outside-air
selector damper
does not operate.
Outlet selector damperDefective outlet selector damperdoes not operate.potentiometer input circuit
Condenser fan doesnot operate when
the air conditioner is
activated.
Air-conditioner graphic
Open-circuited harness betweenCorrect harness.
display does notcontrol panel and air conditioner
function correctly ’control unitI I
Set temperaturereturns to 25°C (112°F)when the ignition
switch is turned ON
and OFF.
Probable causeRemedyRef. page
Defective control panel
Defective air conditioner control
unit
Replace control panel.
Replace air conditioner
control unit.55-56
55-56
Check diagnosis output.Replace defective parts.
Defective outlet selector drive motor
Replace outlet selector
drive motor.
Incorrect engagement of outlet
selector drive motor and outlet
selector damperEngage correctly.
Malfunctioning DEF., FACE, andCorrect DEF., FACE, and
FOOT damperFOOT damper.
Open-circuited harness betweenCorrect harness.outlet selector motor and control unit
Defective control panelReplace control panel.I55-56I
Defective air conditiner control unitReplace air conditioner
control unit.55-56
Defective condenser fan motor relayReplace power relay.
II
Defective water temperature switchReplace water temperature
switch.GROUP 14
Defective condenser fan motor
Replace condenser fan motor.55-33
Defective control panelReplace control panel.I55-56I
Defective air conditioner control unitReplace air conditionercontrol unit.
55-56
Open-circuited power circuitharnessCorrect harness.
Defective air conditioner control unitReplace air conditioner
control unit.55-56TSB Revision
I

55-44FULL AUTO AIR CONDITIONER - Troubleshooting
READING THE “CIRCUIT AND UNIT CHECK”
3. hvqection Of compartment-temperature sensor, outside-air-temperature sensor, and air thermosensor circuits
Air condMnercompressor relay
Compartmenttemperat”re93”SCNFinX”SCH0utsrde.wtemperatureX”SOl
oubleshooting Hints
DlagnosrsNo. 11, 12 [Fix compartment temperature sensor input signal at 25°C (77”F).]
No. 13. 14 [Fix outside-air-temperature sensor input signal at 15°C (59”F).]No. 21, 22 [Fix fin therm0 sensor input signal at -2°C (-356”F).]Air conditioner control unit terminal voltagesI-
ermrnal No.Slgnal nameConditronTerrmnal voltage
5Outside-air-temperature sensorTemperature at sensor 25°C (77°F) (4 kf2)2.2-2.8V
10Sensor power sourceNormally4.8 - 5.2 V
16Compartment temperatureTkmperature at sensor 25°C (77°F) (4 k0)2.3-2.9vsensor
17Fin therm0 sensorTemperature at sensor 25°C (77°F) (4 k0)2.3 - 2.9 Vwhen alr conditioner is OFFA14
-
- Connectors are keyed
by terminal numbers.
Indicates the diagnosis
output code
nur6be.r and
system condition when
the code is output.
Indicates the terminal
number to be checked.Indicates the condition
at terminal check.Indicates the specification criteria.
Where no condition is given in the
“Condition” column, the normal
specification value is given.TSB Revision
1

FULL AUTO AIR CONDITIONER - Troubleshooting
CIRCUIT AND BENCH CHECK
i1 1. Inspection of air conditioner control unit power source circuit 1
,
L
lgniswii
C:
I:Q
6r------.
i
17
Ir~ B27 u
tion
tch 1(IG2)Junction block2:
E
28--6\
3
r-7\--7
LPower source 1I I
AYAir-conditioner control unit
2OFOO61
Troubleshooting Hintsl Air conditioner control unit terminal voltage
Terminal No.Signal nameConditionTerminal voltage
3Backup power sourceNormallyBattery voltage28, 36
Air conditioner control unitIgnition switch ONBattery voltage
power source
27, 35Air conditioner control unit
Normallyov
ground
1 TSB RevisionI

55-46FULL AUTO AIR CONDITIONER - Troubleshooting
2. Inspection of potentiometer circuit
Outlet selector
command c~rcutl
i IComparator&8.
c!
t
Ia
Y[ND conversionA/D conversvmWC”l,CllCUll\/ \,1.y
lo” 6”Air conditioner control unit7‘”
94 72-2t4 3
~1
Air mix damper
potentiometer
z=-
4;t
e11I
Outlet
selector
damper
potentiometer
2OFOO57Troubleshooting Hints
l Diagnosis
No. 31 (Fix air mix damper at MAX. HOT position, or at MAX. COOL position when it is at MAX. COOL
position.)
No. 32 (Fix outlet selector damper at FACE position, or at FACE pgsition when it is at FACE position.)l Air conditioner control unit terminal voltages
Sensor power sourceNormally4.8 - 5.2 V
TSB Revision

FULL AUTO AIR CONDITIONER - Troubleshootinn55-47
3. Inspection of compartment-temperature sensor, outside-air-temperature sensor, and air therm0
sensor circuits
Air conditioner
compressor relay
Air conditioner control
unitA~rconditlonercompiessor
command arllhmew ctrcutc#
Sensorpowersource
Controlled variableIControlled variable
-IIIA/D conversion
Compartment
temperaruresensor
Finsensor
?J
Outside air
temperature
sensor2OFOO60
Troubleshooting Hintsl Diagnosis
No. 11, 12 [Fix compartment temperature sensor input signal at 25°C (77°F).
No. 13, 14 [Fix outside-air-temperature sensor input signal at 15°C
(59”Fj.INo. 21, 22 [Fix fin
therm0 sensor input signal at -2°C (-35.6”FJ.ll Air conditioner control unit terminal voltages
Terminal No.Signal nameConditionTerminal voltage
5Outside-air-temperature sensorTemperature at sensor 25°C (77°F) (4 klR)2.2 - 2.8 V
10Sensor power sourceNormally4.8 - 5.2 V
16Compartment temperatureTemperature at sensor 25°C (77°F) (4 klR)2.3 - 2.9 V
sensor
17Fin therm0 sensorTemperature at sensor 25°C (77°F) (4 k0)2.3 - 2.9 Vwhen air conditioner is OFF
TSB Revision

55-48FULL AUTO AIR CONDITIONER - Troubleshooting
[4. Inspection of water-temperature sensor and photo sensor circuits (
Air conditionercontrol panel
A
{ f*)- Potentiometer
‘>/b Damper drive
motor
\/\,9 Air conditioner
a 7 control unit
Water
temperature
sensor
m

Air conditionerEach sensorcontrol unit&
Air control panel
I.L .Solar radmtmnFin speed arlth-compensating ClrC”itmetIC ClrCUlt#t
A/D convertionND convemon
J2010043
I-
Troubleshooting Hintsl Air conditioner control unit terminal voltages
Terminal No.Signal nameConditionTerminal voltage
19Photo sensor 0llluminance 100,000 lux or more-0.1 to -0.2 v
llluminance less than 0 Iuxov
20Photo sensor 0Normallyov
9Water-temperature sensor 0Switch OFF [Engine coolant temperature
less than 50°C (122”F)]
Battery voltage
Switch ON [Engine coolant temperature
0 V
50°C (122°F) or higher]
1 TSB Revision

FULL AUTO AIR CONDITIONER - Troubleshooting55-495. Inspection of belt lock controller circuit
Compressor relay
tAir conditioner control unitAir conditioner
+control panelAir
condltloner,c.compressor commandAH condmonerarithmetic
circuitcompressor ONstgnal
ComparatorAir condltlonercompressor ON signal20 FOO58
Revolution pickup sensor
LiTroubleshooting Hintsl Air conditioner control unit terminal voltages
Terminal No.
Signal nameConditionTerminal voltage
11Air conditioner outputCompressor ONIO V to battery voltage
TSB Revision

55-50FULL AUTO AIR CONDITIONER - Troubleshooting
6.Inspection of air mix damper, outlet selector damper, inside/outside-air selector damper drive
motor circuits
Air conditioner
Air conditioner control panelcontrol panel
/hOutsideair
f:nsor
Damper
drive motor
\\
” 6

Air conditioner control unit
Poten-tiomet
20N0048
Air conditioner
control panel
23
20N0099
1 TSB Revision