The compressor clutch engagement is controlled by
several components:
• A/C switch on the A/C-heater control panel
• Evaporator temperature sensor
• A/C pressure transducer
• Air temperature sensor
• CAN bus messages
The compressor clutch is de-energized under any of
the following conditions:
• Blocked compressor (thermal fuse in the pulley)
• Low pressure in the system
• Low evaporator temperature
• Hard acceleration (WOT)
• High coolant temperatures
STANDARD PROCEDURE
STANDARD PROCEDURE - COMPRESSOR
CLUTCH AIR GAP
If a new clutch plate and/or clutch pulley are being
used, the air gap between the clutch plate and clutch
pulley must be checked using the following proce-
dure:
(1) Using feeler gauges, measure the air gap
between the clutch plate and the clutch pulley fric-
tion surfaces.
(2) If the air gap is not between 0.5 and 0.9 mm
(0.020 and 0.035 in.), add or subtract shims until the
desired air gap is obtained.
NOTE: The shims may compress after tightening
the compressor shaft bolt. Check the air gap in four
or more places on the clutch plate to verify that the
air gap is still correct. Spin the clutch pulley before
making the final air gap check.
STANDARD PROCEDURE - COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the heater-A/C control in the
Recirculation Mode, the A/C button in the on posi-
tion, the blower motor switch in the highest speed
position, and the engine speed at 1500 to 2000 rpm.
This procedure (burnishing) will seat the opposing
friction surfaces and provide a higher compressor
clutch torque capability.
REMOVAL
The refrigerant system can remain fully-charged
during compressor clutch, pulley, or coil replacement.
The compressor clutch can be serviced in the vehicle.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Disconnect the engine wire harness connector
for the compressor clutch coil from the clutch coil
wire harness connector on the top of the compressor.
(4) Disengage the retainer on the engine wire har-
ness compressor clutch coil lead from the bracket on
the top of the compressor.
(5) Remove the bolt that secures the compressor
clutch to the compressor shaft (Fig. 2). If necessary, a
band-type oil filter wrench or strap wrench can be
placed around the clutch plate to aid in bolt removal.
Fig. 1 Compressor Clutch — Typical
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY AND BEARING
4 - CLUTCH COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
Fig. 2 Compressor Shaft Bolt and Clutch Plate
1 - COMPRESSOR CLUTCH PLATE
2 - COMPRESSOR SHAFT BOLT
VA CONTROLS - FRONT 24 - 9
A/C COMPRESSOR CLUTCH (Continued)
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