Mitsubishi 3000GT Service Manual page 1236

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<Vehicles 200
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Pressure kPa
HEATERS AND MANUAL
AIR CONDITIONING
ON-VEHICLE SERVICE
TEST PROCEDURES
SIGHT GLASS REFRIGERANT LEVEL TEST
The sight glass is a refrigerant level indicator. To check the
refrigerant level, clean the sight glass and start the vehicle
engine. Push the air conditioning button to operate the com-
pressor, place the blower switch to high and move the tempera-
ture control lever to MAX. COOL. After operating for a few
minutes in this manner, check the sight glass.
(1) If the sight glass is clear, the magnetic clutch is engaged,
the compressor discharge line is warm and the compressor
inlet line is cool; the system has a full charge.
(2) If the sight glass is clear, the magnetic clutch is engaged
and there is no significant temperature difference between
compressor inlet and discharge lines; the system has
lost most of its refrigerant charge.
(3) If the sight glass shows foam or bubbles, the system
could be low on refrigerant or the receiver drier is restricted.
The system has to be tested, leak checked then recharged
with refrigerant.
MAGNETIC CLUTCH
(1). Disconnect the wiring to the magnetic clutch.
(2) Connect battery (-) to compressor body.
(3) Connect battery (+) voltage directly to the wiring for the
magnetic clutch.
(4) If the magnetic clutch is normal, there will be a "click".
If the pulley and armature do not make contact ("click"),
there is a malfunction.
RECEIVER DRIER
To Test the Receiver Drier
(1) Operate the unit and check the piping temperature by
touching the receiver drier outlet and inlet.
(2) If there is a difference in the temperatures, the receiver
drier is restricted.
Replace the receiver drier.
DUAL PRESSURE SWITCH (LOW PRESSURE SWITCH)
(1) Turn back the adaptor valve handle all the way and install
it to the low pressure side service valve.
(2) With the gauge manifold low pressure service valves
closed, connect the gauge manifold high pressure side
charging hose to the adaptor valve.
(3) Tighten the adaptor valve handle and open the service
valve.
(4) If there is continuity between the dual pressure switch
terminals when the low pressure side pressure is at the
level of dual pressure switch ON condition shown to the
left, the switch is functioning normally. If not, replace the
switch.
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