stationary electromagnetic A/C clutch field coil with a
zener diode, a pulley bearing and pulley assembly
and a clutch plate (Fig. 1). These components provide
the means to engage and disengage the A/C compres-
sor from the engine accessory drive belt.

On models equipped with the 2.0L and 2.4L Turbo

engines, both the A/C clutch field coil and the pulley
bearing and pulley assembly are retained on the nose
of the compressor with snap rings. On models
equipped with the 2.4L naturally aspirated and 2.7L
engines, the pulley bearing and pulley assembly are
retained on the nose of the compressor with a snap
ring and the A/C clutch field coil is pressed fit to the
nose of the compressor. On all models, the clutch
plate is keyed or splined to the compressor shaft, and
secured with a retainer.

OPERATION

The A/C compressor clutch components provide the

means to engage and disengage the A/C compressor
from the engine accessory drive belt. When the elec-
tromagnetic A/C clutch field coil is energized, it mag-
netically draws the clutch plate into contact with the
clutch pulley and drives the compressor shaft. When
the coil is not energized, the pulley freewheels on the
clutch hub bearing, which is part of the pulley.

A zener diode is connected in parallel with the A/C

clutch field coil. This diode controls the dissipation of
voltage induced into the coil windings by the collaps-
ing of the electromagnetic fields that occurs when the

compressor clutch is disengaged. The zener diode dis-
sipates this induced voltage by regulating a current
path to ground. This arrangement serves to protect
other circuits and components from potentially dam-
aging voltage spikes in the vehicle electrical system
that might occur if the voltage induced in the clutch
coil windings could not be dissipated.

• A/C-heater control in the passenger compart-

ment

• A/C pressure transducer on the A/C discharge

line

• Powertrain control module (PCM) in the engine

compartment

• A/C clutch relay in the power distribution center

(PDC)

• Models equipped the 2.0L and 2.4L Turbo engine

also use a thermal limiter switch mounted to the A/C
compressor to disengage the clutch if compressor sur-
face temperatures become excessive.

The A/C compressor clutch components cannot be

repaired and, if faulty or damaged, they must be
replaced.

DIAGNOSIS AND TESTING

A/C COMPRESSOR CLUTCH COIL

The A/C compressor clutch coil electrical circuit is

controlled by the powertrain control module (PCM)
through the A/C clutch relay. The A/C clutch coil can
be tested by measuring current draw. Begin testing
of a suspected compressor clutch coil problem by per-
forming the preliminary checks.

PRELIMINARY CHECKS

(1) Perform the Heating and A/C System Self

Diagnostics (Refer to 24 - HEATING & AIR CONDI-
TIONING - DIAGNOSIS AND TESTING - HEATING
AND A/C SELF DIAGNOSTICS). If no diagnostic
trouble codes (DTCs) are found in the body control
module (BCM) or the powertrain control module
(PCM), go to Step 2. If any DTCs are found, repair as
required, then proceed to Step 2.

(2) If the A/C compressor clutch still will not

engage, verify the refrigerant charge level (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM LEAKS). If the refrigerant charge level is
OK, go to Step 3. If the refrigerant charge level is not
OK, adjust the refrigerant charge as required, then
proceed to Step 3.

(3) If the A/C compressor clutch still will not

engage, verify the BCM is recieving and sending an
A/C request signal. If OK, go to COIL CURRENT
DRAW TEST. If not OK, repair as required.

Fig. 1 A/C Compressor Clutch - Typical

1 - CLUTCH PLATE
2 - SHAFT KEY (SOME MODELS)
3 - PULLEY AND BEARING
4 - CLUTCH COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING

24 - 12

CONTROLS

COIL CURRENT DRAW TEST

(1) Verify the battery state of charge (Refer to 8 -

ELECTRICAL/BATTERY

SYSTEM/BATTERY

DIAGNOSIS AND TESTING).

(2) Connect an ammeter (0 to 10 ampere scale

selected) in series with the clutch coil feed terminal.
Connect a voltmeter (0 to 20 volt scale selected) to
measure voltage across the battery and the clutch
coil.

(3) With the heater-A/C control in the A/C mode

and the blower at low speed, start the engine and
allow it to run at a normal idle speed.

(4) The A/C compressor clutch should engage

immediately, and the clutch coil supply voltage
should be within two volts of the battery voltage. If
the coil supply voltage is OK, go to Step 5. If the coil
supply voltage is not within two volts of battery volt-
age, test the clutch coil feed circuit for excessive volt-
age drop and repair as necessary.

(5) Refer to the A/C Clutch Coil Specifications

chart for the acceptable A/C clutch coil current draw.
Specifications apply for a work area temperature of
21° C (70° F). If voltage is more than 12.5 volts, add
electrical loads by turning on electrical accessories
until voltage reads below 12.5 volts.

(a) If the compressor clutch coil current reading

is zero, the coil is open and must be replaced.

(b) If the A/C clutch coil current reading is above

specifications, the coil is shorted and must be
replaced.

A/C CLUTCH COIL SPECIFICATIONS

Compressor

Current Draw

Sanden TRS-090

2.0 - 4.15 amps @ 11.5 -
12.5 volts

Visteon HS-15

2.0 - 4.0 amps @ 11.5 -
12.5 volts

STANDARD PROCEDURE

A/C CLUTCH BREAK-IN

After a new A/C compressor clutch has been

installed, cycle the compressor clutch approximately
twenty times (five seconds on, then five seconds off).
During this procedure, set the A/C-heater controls to
the A/C Recirculation Mode, the blower motor 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

2.4L NA/2.7L ENGINES

NOTE: The A/C compressor clutch can be serviced
in the vehicle. The refrigerant system can remain
fully-charged during compressor clutch, pulley and
bearing assembly, or coil replacement.

(1) Disconnect and isolate negative battery cable.
(2) Remove the accessory drive belt (Refer to 7 -

COOLING/ACCESSORY

DRIVE/BELTS-DRIVE

REMOVAL).

(3) Raise and support the vehicle.
(4) Disconnect the wire harness connector from the

clutch field coil connector on the A/C compressor.

(5) Remove the bolts that secure the A/C compres-

sor to the mounting bracket.

(6) Remove the A/C compressor from the mounting

bracket and support the compressor while servicing
the clutch.

(7) Install the compressor clutch holding fixture

(Special Tool 9351 in Kit 9349) onto the clutch plate.
Hold the clutch plate stationary with the holding fix-
ture and remove the clutch bolt (Fig. 2).

NOTE: The clutch plate can be removed from the
compressor shaft by hand or, if required, pressed
off with an 8 x 1.25 mm bolt.

Fig. 2 A/C Clutch Bolt

1 - COMPRESSOR CLUTCH HOLDING FIXTURE
2 - CLUTCH BOLT

CONTROLS

24 - 13

A/C COMPRESSOR CLUTCH (Continued)

(8) Remove the clutch plate from the compressor

shaft. If required, install a 8 x 1.25 mm bolt into the
center of the clutch plate and turn the bolt clockwise
until the clutch plate is completely removed from the
compressor shaft.

(9) Remove the clutch shims from the compressor

shaft.

(10) Remove the snap ring that secures the pulley

and bearing assembly to the compressor with snap
ring pliers (Fig. 3).

NOTE: The pulley and bearing assembly can be
removed from the compressor by hand or, if
required, with a two jaw puller.

(11) Remove the pulley and bearing assembly from

the compressor. If required, install a two jaw puller
and turn the puller center-bolt clockwise until the
pulley and bearing assembly is completely removed
from the front housing hub (Fig. 4).

(12) Remove the screw that secures the clutch coil

wire harness connector bracket to the compressor
(Fig. 5).

(13) Remove the clutch field coil from the compres-

sor with the compressor field coil remover (Special
Tool 9354 in Kit 9349) and a two jaw puller.

2.0L AND 2.4L TURBO ENGINE

NOTE: The A/C compressor clutch can be serviced
in the vehicle. The refrigerant system can remain

fully-charged during compressor clutch, pulley and
bearing assembly, or coil replacement.

(1) Disconnect and isolate negative battery cable.

Fig. 3 Front Housing Hub Snap Ring

1 - SNAP RING PLIERS
2 - SNAP RING

Fig. 4 A/C Clutch Pulley and Bearing

1 - TWO JAW PULLER
2 - PULLEY AND BEARING ASSEMBLY

Fig. 5 A/C Clutch Field Coil

1 - TWO JAW PULLER
2 - COMPRESSOR FIELD COIL REMOVER
3 - CLUTCH FIELD COIL
4 - WIRE HARNESS CONNECTOR
5 - SCREW

24 - 14

CONTROLS

A/C COMPRESSOR CLUTCH (Continued)

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