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10C-34
The compressor has a unique lubrication system. The
crankcase suction bleed is routed through the rotating
wobble-plate for lubrication of wobble-plate bearing.
The rotation acts as an oil separator that removes some of
the oil from the crankcase where it can lubricate the com-
pressor mechanism.
Condenser Core
The condenser assembly in front of the radiator consists
of coils, which carry the refrigerant and cooling fins that
provide the rapid transfer of heat. The air passing through
the condenser cools the high-pressure refrigerant vapor
and causes it to condense it to condense into a liquid.
Receiver-Drier
The sealed receiver-drier assembly is connected between
the condenser and evaporator. It acts as a refrigerant stor-
ing container, receiving liquid and some vapor and refriger-
ant oil from the condenser.
At the bottom of the receiver-drier is the desiccant, which
acts as drying agent for the moisture that may have en-
tered the system. An oil bleed hole is located near the
bottom of the receiver-drier outlet pipe to provide an oil
return path to the compressor. The receiver drier is ser-
viceable as an assembly.
Expansion Valve
The expansion valve can fall in three different positions:
open, closed or restricted.
An expansion valve that fails in open position will result in
a noisy A/C compressor or no cooling. The cause can be
a broken spring, a broken ball or excessive moisture in
the A/C system. If the spring or the ball are found to be
defective, replace the expansion valve. If excessive mois-
ture is found in the A/C system recycle the refrigerant.
A restricted expansion valve will result in low suction pres-
sure and no cooling. This may be caused by debris in the
refrigerant system. If debris is believed to be the cause,
recycle the refrigerant, replace the expansion valve and
replace the receiver-drier.
Evaporator
The evaporator is a device which cools and dehumidifies
the air before it enters the vehicle. High pressure liquid re-
frigerant flows through the expansion tube (orifice) and be-
comes a low pressure gas in the evaporator. The heat in the
air passing through the evaporator core is transferred to the
cooler surface or the core, which cools the air.
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
As the process of heat transfer from the air the evaporator
core surface is taking place, any moisture (humidity) in
the air condenses on the outside surface of the evaporator
core and is drained off as water.
Pressure Relief Valve
The compressor is equipped with a pressure relies valve
which is placed in the system as a safety factor. Under
certain conditions, the refrigerant on the discharge side
may exceed the designed operating pressure at approxi-
mately at 3,171 to 4,137 kPa
(460 to 600 psi) in an R-134a system. Conditions that
might cause this valve to open, such as a defective
pressure transducer, an inoperative cooling fan, etc.,
should be corrected. The refrigerant oil and the refriger-
ant should be replaced as necessary.
Controller
The operation of the A/C system is controlled by the
switches and knob on the control head. This console-
mounted controller contains following control knobs.
Temperature control
• Actuates by cable.
• Raise the temperature of the air entering the vehicle
by sliding to the right or the red portion of the knob.
• Varies the mix of the fresh air from outside the vehicle
with the heated air from inside the vehicle to suit
individual performance.
Mode control
• Actuates by cable.
• Regulates the air distribution between the windshield,
the instrument panel and the floor vents.
Blower control
• Turn on to operate the blower motor at four speeds.
• Turn OFF to stop the blower.
• Operates completely independently from both the mode
control knob and temperature control knob.
• Changes the fan speed in any mode and at any speed.
A/C System Delay Relay
This relay controls the current to A/C system and instantly
delays the A/C operation during starting the engine.
A/C SYSTEM
REXTON SM - 2004.4
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