tery voltage at the cavity for relay terminal 30 at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fuse in the PDC as required.
(2) The relay normally closed terminal (87A) is not
used in this application. Go to Step 3.
(3) The relay normally open terminal cavity (87) is
connected to the compressor clutch coil. There should
be continuity between this cavity and the A/C com-
pressor clutch relay output circuit cavity of the com-
pressor clutch coil wire harness connector. If OK, go
to Step 4. If not OK, repair the open circuit as
required.
(4) The relay coil battery terminal (86) is con-
nected to the fused ignition switch output (run/start)
circuit. There should be battery voltage at the cavity
for relay terminal 86 with the ignition switch in the
On position. If OK, go to Step 5. If not OK, repair the
open circuit to the fuse in the junction block as
required.
(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav-
ity and the A/C compressor clutch relay control cir-
cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit
as required.
ELECTRONIC CYCLING CLUTCH SWITCH (Front
Unit Only)
For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir-
ing Diagrams. Use a volt/ohmmeter to test the elec-
tronic cycling clutch switch. Verify that the
refrigerant system has the correct refrigerant charge.
Check that both the low and high pressure cut-off
switches are functional as described in the Diagnosis
and Testing section of this group before testing the
electronic cycling clutch switch.
(1) Disconnect and isolate the battery negative
cable. Unplug the wire harness connectors at the
electronic cycling clutch switch and the high pressure
cut-off switch. Check for continuity between the
C90A circuit cavities in the body half of the electronic
cycling clutch switch wire harness connector and the
high pressure cut-off switch wire harness connector.
There should be continuity. If OK, go to Step 2. If not
OK, repair the open circuit as required.
(2) Unplug the wire harness connector at the low
pressure cut-off switch. Check for continuity between
the C2 circuit cavities in the body half of the elec-
tronic cycling clutch switch wire harness connector
and the low pressure cut-off switch wire harness con-
nector. There should be continuity. If OK, go to Step
3. If not OK, repair the open circuit as required.
(3) Plug in the wire harness connectors at the low
pressure cut-off and high pressure cut-off switches.
Connect the battery negative cable. Turn the ignition
switch to the On position. Check for battery voltage
at the fused ignition switch output (run) circuit cav-
ity in the body half of the electronic cycling clutch
switch wire harness connector. If OK, go to Step 4. If
not OK, repair the open circuit to the junction block
as required.
(4) Plug in the wire harness connector at the elec-
tronic cycling clutch switch. With the ambient tem-
perature from 20 to 30° C (68 to 90° F), start the
engine and set the heater-A/C mode control switch in
any A/C position. If the compressor clutch fails to
engage, use a DRBIIIt scan tool and the proper
Diagnostic Procedures manual to check the Power-
train Control Module (PCM) and its inputs and out-
puts. If the compressor clutch engages, the clutch
should cycle on and off two to three times per
minute. If the clutch fails to cycle at this rate in
these ambient temperatures, replace the faulty elec-
tronic cycling clutch switch.
NOTE: If the ambient temperature is above 32° C
(90° F) the compressor clutch may stay engaged
and not cycle due to the high heat load. This con-
dition is normal.
EXPANSION VALVE
These tests must be made at an ambient tempera-
ture of 21 to 29° C (70 to 85° F). Disconnect the wire
connector at the low pressure cut off switch. Use a
jumper wire to jumper terminals at the connector.
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 8 Compressor Clutch Relay
DN HEATING AND AIR CONDITIONING 24 - 19
DIAGNOSIS AND TESTING (Continued)
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