CABIN
STW34, STW37, STW40, WSM
10-S29
Functional Check
• The relays described here are used same ones so that
these are interchangeable.
1. Apply the battery voltage across the terminal 1 and 2, and check
for continuity across the terminal 3 and 4.
2. If continuity is not established across the terminal 3 and 4,
replace it.
9Y1211109CAS0051US0
(8) Pressure Switch
Pressure Switch
1) HI Pressure Side
1. Connect the manifold gauge (1) to compressor as following
procedure.
Close the HI and LO pressure valves (6), (7) of manifold gauge
tightly, and connect the charging hoses (4), (5) (red and yellow)
to the respective compressor service valves.
• Be sure to drive out the air in the charging hoses at the
manifold gauge connection end by utilizing the refrigerant
pressure in the refrigerant cycle.
2. Start the engine and set at approx. 1500 min
-1
(rpm). Turn on
the A/C switch, then set the blower switch to HI position.
3. Raise pressure on the HI pressure side of the refrigerant cycle
by covering the condenser front with a corrugated carboard, and
the pressure switch is activated and the compressor magnetic
clutch is turned off. At this time, read the HI pressure gauge of
the manifold gauge. If this pressure reading differs largely with
the setting pressure, replace the pressure switch with a new
one.
2) LO Pressure Side
1. Disconnect 2P connector of pressure switch (8).
2. Measure the resistance with an ohmmeter across the connector
terminals.
3. If 0 ohm is not indicated at normal condition, there is no
refrigerant in the refrigerating cycle because gas leaks or
pressure switch is damaged.
(Reference)
• The resistance of pressure switch is 0 ohm in normal condition,
but it becomes infinity if the pressure is out of factory
specification. Because the pressure switch starts to work.
9Y1211109CAS0047US0
(1) Battery (2) Connector (Relay)
Setting pressure
Factory
specifica-
tion
Pressure
switch OFF
More than
approx. 3.14 MPa
(32 kgf/cm
2
, 455 psi)
Setting pressure
Factory
specifica-
tion
Pressure
switch OFF
Less than
approx. 0.196 MPa
(2.0 kgf/cm
2
, 28.4 psi)
(1) Manifold Gauge
(2) LO Pressure Side Charging Valve
(3) HI Pressure Side Charging Valve
(4) Charging Hose (Red)
(5) Charging Hose (Yellow)
(6) HI Pressure Side Valve
(7) LO Pressure Side Valve
(8) Pressure Switch
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