Mitsubishi 3000GT Service Manual page 1265

HEATERS AND MANUAL AIR CONDITIONING
Low pressure
Engine speed rpm
A: Vehicles using R-12 refrigerant
180 kPa (25 psi)
Vehicles using R-l 34a refrigerant
THERMOSTAT CHECK
(1) Dip the thermostat in engine oil.
(2) Check for continuity across terminals (3) and (6) when
the engine oil is heated.
Standard value:
Continuity at approx. 110°C (230°F) or less
No continuity at approx. 155°C (311°F) or more
00002629
REVOLUTION PICK UP SENSOR CHECK
Measure the resistance between terminals (2) and (5) of the
connector.
Normal resistance:
405 + 35 Sz when ambient temperature is 20°C (68°F)
If the measurement deviates greatly from the above resis-
tance, replace the revolution pick up sensor assembly.
4
CONTROL VALVE CHECK
The control valve detects a low pressure level during the
operation of the air conditioning, and adjusts the amount
of refrigerant to be bypassed.
(1) Operate the air conditioning under a high temperature
load condition (when vehicle interior temperature is high).
(2) Connect a low pressure gauge to the air compressor.
(3) Operate the air conditioning with the engine running at
idle.
(4) Gradually increase the engine speed while observing the
low pressure gauge.
If the valve is normal, the low pressure drops slowly as
the engine speed increases until a pressure of 180 kPa
(25 psi): R-12, 150-200 kPa (20-30 psi): R-134a is
reached, at which point the pressure temporarily ceases
to drop. Then, the pressure again starts dropping as the
engine speed further increases.
If the valve is abnormal, the low pressure drops in direct
proportion to the increase in engine speed without a tem-
porary leveling off at the 180 kPa (25 psi):
If the low pressure drops like this, replace the control
valve.
TSB Revision
55-45
at A point
R-12, 150-200