1991 MITSUBISHI 3000GT relay

FULL AUTO AIR CONDITIONER - Troubleshootina55-41
Symptom
4ir conditioner doeslot operate when the
gnition switch in the
3N position.
nterior temperature
lees not raiseNo warm air coming1ut).
nterior temperatureAoes not lowerNo cold air coming,ut).Probable cause
Open-circuited power circuit harness
Defective control panel
Defective air conditioner control unit
Defective room-temperature sensor
input circuit
Defective air mix damper
potentiometer input circuit
Remedy
Correct harness.
Replace control panel.
Check diagnosis output.
Check diagnosis output.Replace defective parts.
Defective air mix damper drive motorReplace air mix damper drivemotor.
Incorrect engagement of air mix
damper drive motor lever and air mix
damperEngage correctly.
Sticking air mix damper
Open-circuited harness between air
mix damper drive motor and airconditioner control unit
Defective control panel
Defective air conditioner control unit
Correct air mix damper.
Correct harness.
Replace control panel.
Replace air conditioner
control unit.
Defective room-temperature sensor
input circuit
Defective outside-air-temperature
sensor input circuit
Check diagnosis output.
Replace defective parts.
Defective air therm0 sensor input
circuit
Defective refrigerant-temperature
sensor input circuit
Defective air mix damper
potentiometer input circuit
Defective photo sensor
Replace photo sensor.
Defective air mix damper drive motorReplace air mix damper drive
motor.
Incorrect engagement of air mixdamper drive motor lever and airmix damper
Engage correctly.
Sticking air mix damper
Open-circuited harness between air
mix damper drive motor and airconditioner control unit
Open-circuited harness between
photo sensor and air conditioner
control unit
Correct air mix damper.
Correct harness.
Correct harness.
Defective air-conditioner compressorReplace.
relay in the relay boxTSB Revision
Ref. page
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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 - 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

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

55-52FULL AUTO AIR CONDITIONER - Troubleshooting
7. Inspection of power transistor and blower motor relay circuitsllower
Potor t?lay
El12
3 4
Ignitionswitch IG2Blower motor
relay
Air conditioner
-control panel
IWY/\2’
a.T
Air conditioner control unit
Fan speed anth-mete circw
)lardiatlon‘nsor2OFOO59
Troubleshooting Hintsl Air conditioner control unit terminal voltages
Power transistor baseTSB Revision