Mitsubishi 3000GT Service Manual page 1291

FULL AUTO AIR CONDITIONING - Troubleshooting
SERVICE DATA
Item Inspection
Method
no. point
11 Interior tem- Measure resistance of sen-
perature sen- sor when interior tempera-
ture is 25°C (77°F).
sor
Measure voltage across ter-
minal 16 of air conditioning
control unit and ground
wheninteriortemperatureis
25°C (77°F).
13 Air inlet sen- Measure resistance of sen-
sor sor when ambient tempera-
ture is 25°C (77°F).
Measurevoltageacrosster-
minal (5) of air conditioning
control unit and around
when ambient temperature
is 25°C (77°F)
15 Engine cool- Measure resistance of sen-
ant tempera- sor when engine coolant
ture sensor temperature is 22.5 to
Measurevoltageacrosster-
minal (5) of air conditioning
control unit and ground
when engine coolant tem-
perature is 22.5 to 30.5%
(57.6 to 86.9"F).
21 Air Measure resistance of sen-
sensor sor when sensor's sensing
Measurevoltageacrosster-
minal 17 of air conditioning
control unit and ground
perature is 25°C (77°F).
air
31 Blend Refer to P.55-75.
damper po-
tentiometer
Measure voltage across
terminal (5)of air condition-
ing control unit and ground
when potentiometer is in
MAX. COOL position.
33 Mode selec- Refer to P.55-75.
tion damper
potentiome-
ter
Measure voltage across ter-
minal (5) of air conditioning
when potentiometer is in
FACE position.
Normal condition
Approx. 4 k.Q
In approx. 2.3-2.9 V range
Approx. 4 kS2
In approx. 2.2-2.8 V range
Conductive
Approx. 12 V
Approx. 4 w2
In approx. 2.3-2.9 V range
In approx. 0.1-0.3 V range
In approx. 0.1-0.3 V range
Revision
TSB
Probable cause
Detective interior tempera-
ture sensor
ature sensor.
Open-circuited harness be- Correct harness.
tween interior temperature
sensor and air conditioning
control unit
Poor connection of air
Correct connector con-
conditioning control unit nection or replace air
connector or defective air
conditioning control unit.
conditioning control unit
Defective air inlet sensor Replace air inlet sensor.
Open-circuited harness be- Correct harness.
tweenairinletsensorandair
conditioning control unit
Poor connection of air- Correct connector con-
conditioning control unit nection or replace air
connector or defective air conditioning control unit.
conditioning control unit
Defective engine coolant Replace engine coolant
temperature sensor
temperature sensor.
Open-circuited harness be- Correct harness.
tween engine coolant tem-
perature sensor and air
conditioning control unit
Poor connection of air Correct connector con-
conditioning control unit nection or replace air
connector or defective air conditioning control unit
conditioning control unit
Defective air therm0 sensor Replace air therm0 sen-
sor
Open-circuited harness be- Correct harness.
tween air therm0 sensor
and air conditioning control
unit
Poor connection of air Correct connector con-
conditioning control unit nection or replace air
conditioning control unit.
connector or defective air
conditioning control unit
Defective blend air damper Replace blend airdamp-
potentiometer er potentiometer.
Open-circuited harness be- Correct harness.
tween blend air damper po-
tentiometer and air condi-
tioning control unit
Poor connection of air Correct connector con-
conditioning control unit nection or replace air
connector or defective air conditioning control unit.
conditioning control unit
Defective mode selection Replace mode selection
damper potentiometer damper potentiometer.
Open-circuited harness be- Correct harness.
tween mode selection
damper potentiometer and
air conditioning control
Correct connector con-
Poor connection of air
conditioning control unit nection or replace air
connector or defective air conditioning control unit.
conditioning control unit
55-71
Remedy