CLUTCH-A/C COMPRESSOR
DESCRIPTION
NOTE: Denso 10S17 A/C clutch assembly shown.
Visteon HS-18 compressor similar.
The A/C compressor clutch assembly consists of a
stationary electromagnetic field coil (4), bearing and
pulley assembly (3), shims (7) and a clutch plate (2)
that is splined to the compressor shaft and secured by
a bolt (1). These components provide the means to
engage and disengage the A/C compressor from the
engine accessory drive belt.
The A/C clutch bearing and pulley assembly on both
A/C compressors are retained to the front of the com-
pressor with a snap ring (6). The A/C clutch field coil
on the Denso 10S17 A/C compressor is also retained
to the front of the compressor using a snap ring (5).
The field coil on the Visteon HS-!8 compressor is
pressed onto the front of the compressor.
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 electromagnetic A/C clutch field coil is energized, it magnetically draws the
clutch plate into contact with the clutch pulley and drives the compressorshaft. When the coil is not energized, the
pulley freewheels on the clutch hub bearing, which is part of the pulley assembly.
A/C compressor clutch engagement is controlled by the powertrain controlmodule (PCM) or the engine control mod-
ule (ECM), depending on engine application. When the A/C-heater control is set to any A/C position, it sends a
request signal on the CAN-B bus to the totally integrated power module (TIPM), which then transfers the request on
the CAN-C Bus to the PCM/ECM, which determines if operating conditions arecorrect for A/C clutch engagement.
When all operating conditions have been met, the PCM/ECM sends a signal on adedicated hard-wired circuit back
to the totally integrated power module (TIPM) to energize the internal A/Cclutch high side driver. When energized,
the A/C clutch high side driver provides battery current to the A/C clutch field coil.
The A/C clutch control system is diagnosed using a scan tool (Refer to 24 - HVAC Electrical Diagnostics and to 9
- Engine Electrical Diagnostics for more information).
The A/C compressor clutch components cannot be repaired and, if faulty or damaged, they must be replaced.
DIAGNOSIS AND TESTING
A/CCOMPRESSORCLUTCHCOIL
The A/C compressor clutch coil electrical circuit is controlled by the powertrain control module (PCM) or the engine
control module (ECM) (depending on engine application) through the totally integrated power module (TIPM) (Refer
to 24 - HEATING & AIR CONDITIONING/CONTROLS/COIL-A/C COMPRESSOR CLUTCH -OPERATION for more
information). Begin testing of a suspected compressor clutch coil problem by performing the preliminary checks.
PRELIMINARY CHECKS
1. Using a scan tool, check for diagnostic trouble codes (DTCs) in the A/C-heater control, TIPM, PCM/ECM and if
equipped with the 8.3L engine, the gateway module. If no DTCs are found, go to Step 2. If any DTCs are found,
repair as required.
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 refrig-
erant charge level is OK, go to TESTS . If the refrigerant charge level is notOK, adjust the refrigerant charge as
required.
TESTS
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 A/C-heater control in the A/C mode and the blower motor 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 voltage, test the clutch coil feed circuit for excessive voltage drop and repair as necessary.
5. For the acceptable A/C clutch coil current draw specifications refer to24 - HEATING & AIR CONDITIONING -
SPECIFICATIONS. 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.
STANDARD PROCEDURE
A/C CLUTCH PLATE INSPECTION
NOTE: The A/C clutch can be serviced inthe vehicle. The refrigerant systemcan remain fully-charged dur-
ing compressor clutch, pulley and bearing assembly, or coil replacement.
Examine the friction surfaces of the pulley and the
clutch plate (2) for wear. The pulley and clutch plate
should be replaced if there is excessive wear or scor-
ing.
If the friction surfaces are oily, inspect the shaft and
nose area of the A/C compressor (1) for refrigerant oil.
If refrigerant oil is found, the compressor shaft seal is
leaking and the A/C compressor must be replaced.
Check the pulley bearing for roughness or excessive
leakage of grease. Replace the pulley and bearing
assembly, if required.
A/C CLUTCH BREAK-IN
After a new A/C compressor clutch hasbeen installed, cycle the compressorclutch approximately 20 times (5 sec-
onds on, then 5 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.
6. Install the clutch plate (4) onto the front of the A/C
compressor (5).
7. Install the compressor shaft bolt (3). Tighten the
bolt to 19 Nꞏm (168 in. lbs.).
NOTE: The shims may compress after tightening
the shaft bolt. Check the air gap in four or more
places to verify the air gap is correct. Spin the pul-
ley before performing a final check of the air gap.
NOTE: On models with the clutch plate recessed
intothepulley,usea90°wiregapgaugetomea-
sure the clutch air gap. On other models, use a
blade type feeler gauge to measure the air gap.
8. With the clutch plate assembled tight against the
shim(s), measure the air gap between the clutch
plate and the pulley and bearing assembly. The air
gap should be between 0.35 - 0.60 mm (0.014 -
0.024 in.). If the air gap is not between specifica-
tions, add or subtract shims as needed until the
correct air gap is obtained.
CAUTION: Be certain that the compressor clutch field coil wire harness is properly routed so that it is not
pinched between the A/C compressor and the field coil connector bracket.
9. Carefully route the compressor clutch field coil wire lead behind the connector bracket (2).
10. Install the compressor clutch fieldcoil connector (1) onto the connector bracket.
11. Position the A/C compressor to the engine and install the retaining bolts (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING/COMPRESSOR-A/C - INSTALLATION).
12. Connect the engine wire harness to the compressor clutch field coil connector.
13. Install the accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/BELTS-DRIVE - INSTALLATION).
14. Reconnect the negative battery cable.
VISTEON A/C COMPRESSOR
1. Position the A/C clutch field coil (1) squarely onto
the front of the A/C compressor (2).
CAUTION: Position the A/C clutch field coil so that
the coil positioning tabs and the wire harness lead
are oriented in the correct direction. Failure to cor-
rectly position the fieldcoil on the A/C compres-
sor will result in field coil damage.
2. Align the field coil positioning tabs to the recessed
area at the front of the A/C compressor and install
the clutch field coil onto the compressor using a
two jaw puller (3), compressor field coil installer
(Special Tool 9352 in Kit 9349) (4) and the com-
pressor field coil installer spacer (Special Tool 9353
in Kit 9349) (5).
7. Verify that there is adequate clearance for the
clutch field coil wire lead and connector (4)
between the compressor housing and the pulley.
NOTE: When installing an original or a new clutch
assembly, try the original shims first. When install-
ing a clutch onto a compressor that previously did
not have a clutch, use the 1.0, 0.50 and 0.13 milli-
meter (0.040, 0.020 and 0.005 inch) shims from the
clutch hardware package which is provided with
the new clutch.
8. Install the clutch shims onto the compressor shaft.
9. Using compressor clutch holding fixture (Special
Tool 9351 in Kit 9349) (1), install the bolt (2) that
secures the clutch plate (3) to the A/C compressor
(5). Hold the clutch plate stationary with the holding
fixture and tighten the bolt to 15 Nꞏm (133 in. lbs.).
10. Using a feeler gauge (1), check the air gap
between the clutch plate (2) and the pulley and
bearing assembly (3). If the air gap is not 0.35 to
0.75 millimeter (0.014 to 0.030 inch), add or sub-
tract shims as required.
11. Position the A/C compressor (4) onto the mount-
ing bracket.
12. Install the bolts that secure the A/C compressor to
themountingbracket.Tightentheboltsto23Nꞏm
(17 ft. lbs.).
13. Connect the engine wire harness to the compres-
sor clutch field coil connector (5).
14. Lower the vehicle.
15. Install the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
16. Reconnect the negative battery cable.
17. Perform the Clutch Break-in Procedure (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS/A/C COMPRESSOR CLUTCH - STANDARD PROCE-
DURE).
DIAGNOSIS AND TESTING
A/C COMPRESSOR
When investigating an A/C system related noise, you must first know the conditions under which the noise occurs.
These conditions include: weather, vehicle speed, transmission in gear or neutral, engine speed, engine tempera-
ture, and any other special conditions. Noises that develop during A/C operation can often be misleading. For exam-
ple: What sounds like a failed front engine bearing or connecting rod, may be caused by loose bolts, nuts, mounting
brackets or a loose compressor clutch assembly.
Drive belts are speed sensitive. At different engine speeds and dependingupon drive belt tension, drive belts can
develop noises that are mistaken for an A/C compressor noise. Improper drive belt tension can cause a misleading
noise when the compressor clutch is engaged, which may not occur when the compressor clutch is disengaged.
Check the accessory drive belt condition and tension as described in Cooling before beginning this procedure.
1. Select a quiet area for testing. Duplicate the complaint conditions as much as possible. Turn the A/C compressor
On and Off several times to clearly identify the compressor noise. Listen to the A/C compressor while the clutch
is engaged and disengaged. Probe the A/C compressor with an engine stethoscope or a long screwdriver with
the handle held to your ear to better localize the source of the noise.
2. Loosen all of the compressor mounting hardware and retighten. Check thecompressor clutch retainer. Be certain
that the clutch field coil is mounted securely to the A/C compressor, and that the clutch plate and pulley are
properly aligned and have the correct air gap (Refer to 24 - HEATING & AIR CONDITIONING/CONTROLS/
CLUTCH-A/C COMPRESSOR - INSTALLATION).
3. To duplicate high-ambient temperature conditions (high head pressure), restrict the air flow through the A/C con-
denser. Install a manifold gauge set or a scan tool to be certain that the discharge pressure does not exceed
2760 kPa (400 psi).
4. Check the refrigerant system plumbing for incorrect routing, rubbing or interference, which can cause unusual
noises. Also check the refrigerant lines and hoses for kinks or sharp bendsthat will restrict refrigerant flow, which
can cause noises (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - DESCRIPTION - REFRIGER-
ANT LINES).
5. If the noise is from opening and closing of the high pressure relief valve, recover, evacuate and recharge the
refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY), (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT SYSTEM EVACUATE) and (Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYSTEM CHARGE). If the high pressure relief
valve still does not seat properly, replace the A/C compressor (Refer to 24- HEATING & AIR CONDITIONING/
PLUMBING/COMPRESSOR-A/C - REMOVAL).
6. If the noise is from liquid refrigerant slugging in the A/C suction line,replace the A/C accumulator (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/ACCUMULATOR-A/C - REMOVAL) and check the refrigerant oil
level and the refrigerant system charge (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIG-
ERANT OIL - STANDARD PROCEDURE - REFRIGERANT OIL LEVEL) (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING- STANDARD PROCEDURE - REFRIGERANT SYSTEM CHARGE).
7. If a slugging condition still exists after replacing the A/C accumulator, then replace the A/C compressor (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING/COMPRESSOR-A/C - REMOVAL) and repeat Step 1.
REMOVAL
3.7L/4.7L ENGINES
WARNING: Refer to the applicable warnings and cautions for this system before performing the following
operation (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS). Failure to follow the warnings and cautions could result
in possible personal injury or death.
NOTE: The A/C compressor may be removed and repositioned without disconnecting the refrigerant lines or
discharging the refrigerant system. Discharging is not necessary if servicing the compressor clutch, clutch
coil, engine, engine cylinder head or the generator.
1. Recover the refrigerant from the refrigerant system
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY).
2. Disconnect and isolate the negative battery cable.
3. Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/BELTS-DRIVE -
REMOVAL).
4. Disconnect the wire harness connector from the
A/C compressor clutch coil connector (4).
5. Remove the bolts (5) that secure the A/C suction
line (1) and the A/C discharge line (3) to the A/C
compressor (2).
6. Disconnect the refrigerant lines from the A/C com-
pressor and remove and discard the seals.
7. Install plugs in, or tape over all of the opened
refrigerant line fittings and the compressor ports.
8. Remove the four bolts (1) that secure the A/C com-
pressor (2) to the cylinder block (3).
9. Remove the A/C compressor from the engine
compartment.
INSTALLATION
3.7L/4.7L ENGINES
NOTE: If a replacement A/C compressor is being installed, be certain to check the refrigerant oil level. See
Refrigerant Oil Level in this group for the procedures. Use only refrigerant oil of the type recommended for
the compressor in the vehicle.
1. Position the A/C compressor (2) onto the accessory
mounting bracket (4).
2. Install and tighten the bolts in the following
sequence:
Install bolt (3) and hand tighten.
Install bolt (6) and hand tighten.
Install bolt (1) and hand tighten.
Tightened bolt (3) to 40 Nꞏm (30 ft. lbs.).
Tightened bolt (6) to 55 Nꞏm (41 ft. lbs.).
Tightened bolt (1) to 55 Nꞏm (41 ft. lbs.).
Tightened bolt (5) to 55 Nꞏm (41 ft. lbs.).
3. Remove the tape or plugs from the opened refrig-
erant line fittings and the compressor ports.
4. Lubricate new seals with clean refrigerant oil and
install them onto the refrigerant line fittings. Use
only the specified seals as they are made of a spe-
cial material for the R-134a system. Use only
refrigerant oil of the type recommended for the A/C
compressor in the vehicle.
5. Install the A/C suction line (5) and the A/C dis-
charge line (9) onto the A/C compressor (6).
6. Install the nuts (4) that secure the refrigerant lines
to the A/C compressor. Tighten the nuts to 20 Nꞏm
(15 ft. lbs.).
7. Install the accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/BELTS-DRIVE - INSTAL-
LATION).
8. Reconnect the negative battery cable.
9. Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).
10. Charge the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM CHARGE).
5.7L ENGINE
NOTE: Be certain to check the refrigerant oil level if the A/C compressor isbeing replaced. See Refrigerant
Oil Level in this group for the procedures. Use only refrigerant oil of the type recommended for the A/C
compressor in the vehicle.
1. Position the A/C compressor (2) into the engine
compartment.
2. Install and tighten the bolts that secure the A/C
compressor to the mounting bracket (4) in the fol-
lowing sequence:
Install the two lower bolts (1) and hand tighten.
Install the rear bolt (3) and hand tighten.
Tightenthetwolowerboltsto40Nꞏm(30ft.
lbs.).
Tighten the rear bolt to 55 Nꞏm (41 ft. lbs.).
3. Install the generator support bracket (Refer to 8 -
ELECTRICAL/CHARGING/GENERATOR -
INSTALLATION).
4. Remove the tape or plugs from the opened refrig-
erant line fittings and the compressor ports.
5. Lubricate new O-rings and dual plane seals with
clean refrigerant oil and install them onto the refrig-
erant line fittings. Use only the specified seals as
they are made of a special material for the R-134a
system. Use only refrigerant oil of the type recom-
mended for the A/C compressor in the vehicle.
6. Install the A/C discharge line (1) and the A/C suc-
tion line (5) onto the A/C compressor (6).
7. Install the nuts (4 and 7) that secure the refrigerant
lines to the A/C compressor. Tighten the nuts to 20
Nꞏm (15 ft. lbs.).
8. Connect the wire harness connector to the clutch
field coil connector and the A/C pressure trans-
ducer (8).
9. Install the accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/BELTS-DRIVE - INSTAL-
LATION).
10. Reconnect the negative battery cable.
11. Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIGERANT SYSTEM EVAC-
UATE).
12. Charge the refrigerant system (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM CHARGE).
5.9L DIESEL ENGINE
NOTE: Be certain to check the refrigerant oil level if the A/C compressor isbeing replaced. See Refrigerant
Oil Level in this group for the procedures. Use only refrigerant oil of the type recommended for the A/C
compressor in the vehicle.