LOW PRESSURE CYCLING CLUTCH SWITCH

Before performing diagnosis of the low pressure
cycling clutch switch, be certain that the switch is
properly installed on the accumulator fitting. If the
switch is too loose it may not open the Schrader-type
valve in the accumulator fitting, which will prevent
the switch from correctly monitoring the refrigerant
system pressure. Remember that lower ambient tem-
peratures, below about -1° C (30° F), during cold
weather will open the switch contacts and prevent
compressor operation due to the pressure/tempera-
ture relationship of the refrigerant.

Also verify that the refrigerant system has the cor-
rect refrigerant charge. See Refrigerant System
Charge in the Service Procedures section of this
group for more information.

For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir-
ing Diagrams.

(1) Disconnect and isolate the battery negative cable.

(2) Unplug the low pressure cycling clutch switch
wire harness connector from the switch on the accu-
mulator fitting.

(3) Install a jumper wire between the two cavities
of the low pressure cycling clutch switch wire har-
ness connector.

(4) Connect a manifold gauge set to the refrigerant
system service ports. See Refrigerant System Service
Equipment and Refrigerant System Service Ports in
the Description and Operation section of this group
for more information.

(5) Connect the battery negative cable.

(6) Place the heater-A/C mode control switch ****
in any A/C position and start the engine.

(7) Check for continuity between the two terminals of
the low pressure cycling clutch switch. There should be
continuity with a suction pressure reading of 262 kPa
(38 psi) or above, and no continuity with a suction pres-
sure reading of 141 kPa (20.5 psi) or below. If OK, test
and repair the A/C switch sense circuit as required. If
not OK, replace the faulty switch.