refrigerant type MERCEDES-BENZ SPRINTER 2006 Service Manual

Compres SO Accel (Compressor Shut Off - Due
To Acceleration)
The Engine Control Module transmits this data. A
status of9YES9indicates that the compressor shut
off because of an acceleration request. A status of
9NO9indicates that there is no acceleration request.
If shut off due to an acceleration request, the
compress will switch on again after 20 seconds. In
addition, the original acceleration request can no
longer exist for the ECM to acknowledge a subse-
quent request. In the event of a CAN Bus commu-
nication failure,9NO9is displayed as a substitute
value.
Compres SO W/E-Off (Compressor Shut Off -
Due to Emergency Off)
The Engine Control Module transmits this data. A
status of9YES9indicates that the compressor shut
off because of an emergency off request. A status of
9NO9indicates that there is no emergency off re-
quest. In the event of a CAN Bus communication
failure, the last stored value is displayed as a
substitute value.
Auxiliary Fan
The ATC Module transmits this data. A status of
9ON9indicates that the auxiliary fan is operational.
A status of9OFF9indicates that the auxiliary fan is
not operational. The Auxiliary Fan normally oper-
ates when refrigerant head pressure exceeds 290
PSI and coolant temperature exceeds 221ÉF. In the
event of a CAN Bus communication failure, 257ÉF is
displayed for coolant temperature (in Sensors) and
the Auxiliary Fan will run continuously.
Light PB CTRL Module
This input displays a status of9Bright9for positive
dimmer switch operation and9Dimmed9for nega-
tive dimmer switch operation. In the event of a CAN
Bus communication failure,9Bright9is displayed.
3.3.2 CABIN HEATER MODULE (CHM) &
HEATER BOOSTER MODULE (HBM)
3.3.2.1 SYSTEM DESCRIPTION
WARNING: NEVER OPERATE THE HEATER
IN AN ENCLOSED AREA THAT DOES NOT
HAVE EXHAUST VENTILATION FACILITIES.
ALWAYS VENT THE HEATER'S EXHAUST
WHEN OPERATING THE HEATER. REFER TO
(VENTING THE HEATER'S EXHAUST(
BELOW FOR PROPER EXHAUST VENTING
INSTRUCTIONS. FAILURE TO FOLLOW
THESE INSTRUCTIONS CAN RESULT IN
PERSONAL INJURY OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO
COOL BEFORE PERFORMING A COMPONENT
INSPECTION/REPAIR/REPLACEMENT. FAILURE
TO FOLLOW THESE INSTRUCTIONS CAN
RESULT IN PERSONAL INJURY OR DEATH.
WARNING: ALWAYS DISCONNECT THE
VEHICLE'S BATTERY PRIOR TO
PERFORMING ANY TYPE OF WORK ON THE
HEATER ASSEMBLY. FAILURE TO FOLLOW
THESE INSTRUCTIONS CAN RESULT IN
PERSONAL INJURY OR DEATH.
WARNING: NEVER ATTEMPT TO REPAIR THE
HEATER ASSEMBLY OR ANY OF ITS
INTERNAL COMPONENTS. ALWAYS
PERFORM HEATER COMPONENT
REPLACEMENT IN ACCORDANCE WITH THE
SERVICE INFORMATION. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN
RESULT IN PERSONAL INJURY OR DEATH.
CAUTION: Always Perform The Heater
Pre-Test (In The Diagnostic Procedures) Prior
To Performing Any Other Test On The Heater
For The Test Result To Be Valid.
NOTE: Do not disconnect the vehicle's
battery or the heater's main power-supply
while the heater is in operation or in
run-down mode. Failure to follow these
instructions may result in excess emissions
from the heater.
NOTE: Failure to prime the Dosing Pump
after draining the fuel line will prevent heater
activation during the first attempt to start the
unit. This may also set a Diagnostic Trouble
Code (DTC) in the control unit's memory. Do
not perform the Dosing Pump Priming
Procedure if an attempt was made to start the
heater without priming the Dosing Pump
first. This will put excess fuel in the heater
module and cause smoke to emit from the
heater's exhaust pipe when heater activation
occurs.
NOTE: Waxed fuel can obstruct the fuel line
and reduce flow. Check for the appropriate
winter grade fuel and replace as necessary.
The Cabin Heater Assembly and Heater Booster
Assembly are supplemental type heaters designed
to pre-heat the engine's coolant in order to supply
the vehicle's occupants with heat prior to the engine
7
GENERAL INFORMATION

(11) Install the torque converter access plate. Refer
to (Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - NAG1 - INSTALLATION) for correct
sequence and torque specification.
(12) Install the transmission cooler lines to trans-
mission. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - NAG1 - INSTALLATION) for
correct sequence and torque specification.
(13) Connect the engine valley drain hose to the
transmission (Fig. 5).
(14) Install transmission electrical connector and
shifter hardware. Refer to (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - NAG1 - INSTAL-
LATION) for correct sequence and torque
specification.
(15) Install the steering gear and tighten in two
stages. 25 N´m (18.5 lbs. ft.), then 45 N´m (33 lbs. ft.)
plus 90É.
(16) Install the starter.
(17) Connect the ground strap (left side).
(18) Align and install the exhaust and bracket
(Refer to 11 - EXHAUST SYSTEM/EXHAUST PIPE -
INSTALLATION).
(19) Lower the vehicle.
(20) Install the lower heater housing and filter.
(21) Install the air inlet hose, CCV breather and
CCV heater at the turbocharger (Fig. 4).
(22) Connect the coolant supply and return hoses.
(23) Connect the brake booster vacuum hose at the
vacuum pump.(24) Connect the fuel lines at the filter assembly
(Fig. 9).
(25) Connect the power steering hoses.
(26) Install the radiator/charge air cooler and
hose(s) assemblies (Refer to 7 - COOLING/ENGINE/
RADIATOR - INSTALLATION).
(27) Install A/C condenser and fan assemblies Con-
nect the fan harness connector.
(28) Connect the refrigerant lines.
(29) Install a air conditioning receiver/drier (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING/RECEIVER / DRIER - INSTALLATION).
(30) Connect the upper and lower radiator hoses.
(31) Connect the transmission lines at the radia-
tor.
(32) Install air cleaner housing and connect the air
inlet duct and air flow sensor.
(33) Connect the charge air cooler hose at intake
manifold. (Refer to 9 - ENGINE/AIR INTAKE SYS-
TEM/AIR CLEANER HOUSING - INSTALLATION).
(34) Route the engine wiring harness inside the
vehicle and connect.
(35) Install the turbocharger heat shield.
(36) Install the front grille and fascia assembly.
(37) Connect the negative battery cable.
(38) Check and fill engine oil (Refer to LUBRICA-
TION & MAINTENANCE/FLUID TYPES - SPECIFI-
CATIONS).
Fig. 8 CRANKSHAFT POSITION SENSOR
1 - ENGINE BLOCK
2 - WIRING HARNESS CONNECTOR
3 - CRANKSHAFT POSITION SENSOR
4 - STARTER SOLENOID
Fig. 9 FUEL FILTER
1 - FUEL SUPPLY FROM TANK
2 - FUEL SUPPLY TO HIGH PRESSURE PUMP
3 - POWER STEERING RESERVOIR
4 - FUEL FILTER
5 - OIL FILTER
6 - WATER IN FUEL SENSOR
9 - 10 ENGINEVA

OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch into contact with the 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.
The compressor clutch engagement is controlled by
several components:
²A/C switch on the A/C-heater control panel
²Evaporator temperature sensor
²A/C pressure transducer
²Air temperature sensor
²CAN bus messages
The compressor clutch is de-energized under any of
the following conditions:
²Blocked compressor (thermal fuse in the pulley)
²Low pressure in the system
²Low evaporator temperature
²Hard acceleration (WOT)
²High coolant temperatures
STANDARD PROCEDURE
A / C 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 specifications
(Refer to 24 - HEATING & AIR CONDITIONING -
SPECIFICATIONS), 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.
A / C 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) Remove the retainer securing the compressor
clutch coil lead 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 A/C Compressor Clutch
1 - BOLT
2 - CLUTCH PLATE
3 - PULLEY AND BEARING
4 - FIELD COIL
5 - SNAP RING
6 - SNAP RING
7 - SHIM (2)
VACONTROLS-FRONT 24 - 9

front cover of the compressor. Be certain that the
snap ring is properly fully and properly seated in the
groove.
(6) If the original clutch plate and clutch pulley
are to be reused, reinstall the original shim(s) on the
compressor shaft against the shoulder. If a new
clutch plate and/or clutch pulley are being used,
install a trial stack of shims 1.0 mm (0.040 in.) thick
on the compressor shaft against the shoulder.
(7) Install the clutch plate onto the compressor
shaft.
(8) Install and tighten the compressor shaft bolt. If
necessary, a band-type oil filter wrench or a strap
wrench can be placed around the clutch plate to aid
in bolt tightening. Tighten the bolt to 17.5 N´m (155
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 still correct. Spin the
pulley before performing a final check of the air
gap.
(9) If a new clutch plate and/or clutch pulley are
being installed, the air gap between the clutch plate
and clutch pulley must be checked (Refer to 24 -
HEATING & AIR CONDITIONING/CONTROLS/A/C
COMPRESSOR CLUTCH - STANDARD PROCE-
DURE).
(10) Install the retainer that secures the compres-
sor clutch coil lead to the top of the compressor.
(11) Reconnect the engine wire harness connector
to the clutch coil lead on the top of the compressor.
(12) Reinstall the serpentine accessory drive belt
(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS - INSTALLATION).
(13) Reconnect the battery negative cable.
(14) If a new clutch plate and/or clutch pulley are
being installed, the new clutch components must be
burnished (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS/A/C COMPRESSOR CLUTCH
- STANDARD PROCEDURE).
A / C COMPRESSOR CLUTCH
COIL
DIAGNOSIS AND TESTING
A / C COMPRESSOR CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the ATC control module
which is integral to the heater-A/C control. Begin
testing of a suspected compressor clutch coil problem
by performing the ATC Function Test using the
DRBIIItscan tool.PRELIMINARY CHECKS
(1) If no diagnostic trouble codes (DTCs) are found
in the A/C-heater control or the powertrain control
module (PCM), 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 refrigerant charge level is
OK, go to TESTS. If the refrigerant charge level is
not OK, 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 volt-
age, test the clutch coil feed circuit for excessive volt-
age drop and repair as necessary.
(5) For the acceptable A/C clutch coil current draw
specifications refer to 24 - HEATING & AIR CONDI-
TIONING - SPECIFICATIONS. Specifications apply
for a work area temperature of 21É C (70É F). If volt-
age is more than 12.5 volts, add electrical loads by
turning on electrical accessories until voltage reads
below 12.5 volts.
(a) If the A/C 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 HEATER CONTROL
DESCRIPTION
This ATC system uses a combination of electrical
and mechanical controls. These controls provide the
vehicle operator with a number of setting options to
help control the climate and comfort within the vehi-
cle.
The A/C-heater control is located on the instrument
panel inboard of the steering column and below the
24 - 12 CONTROLS-FRONTVA

BLOWER MOTOR SWITCH
DESCRIPTION
The blower motor is controlled by a thumbwheel-
type blower motor control, mounted in the A/C-heater
control (Fig. 17). The switch allows the selection of
four blower motor speeds with the ignition switch in
the On position.
NOTE: The blower motor will operate only at the
lowest speed when the Residual Engine Heat Utili-
zation (REST) function is selected, regardless of the
blower speed setting on the A/C-heater control.
OPERATION
When the ignition is turned to On, the integral
blower motor switch within the ATC A/C-heater con-
trol supplies power to the blower motor switch. The
switch directs power to the individual blower driver
circuits through the blower motor resistor block to
the blower motor and then to ground.
The blower motor switch cannot be adjusted or
repaired, and if faulty or damaged, the A/C-heater
control must be replaced (Refer to 24 - HEATING &
AIR CONDITIONING/CONTROLS/A/C HEATER
CONTROL - REMOVAL).
DIAGNOSIS AND TESTING
BLOWER MOTOR SWITCH
The blower motor switch can be diagnosed by using
the DRBIIItscan tool. Refer to Body Diagnostic Pro-
cedures. For circuit descriptions and diagrams, refer
to the appropriate wiring information.
EVAPORATOR TEMPERATURE
SENSOR
DESCRIPTION
The evaporator temperature sensor measures the
temperature of the conditioned air downstream of the
A/C evaporator (Fig. 18). The evaporator temperature
sensor is an electrical thermistor within a molded
plastic case that is inserted into the HVAC housing
near the coldest point of the A/C evaporator. Two ter-
minals within the connector receptacle connect the
sensor to the vehicle electrical system through a wire
lead and connector of the HVAC wire harness.
The external location of the evaporator tempera-
ture sensor allows the sensor to be removed or
installed without disturbing the refrigerant in the
A/C system.
OPERATION
The evaporator temperature sensor monitors the
temperature of the A/C evaporator. The sensor will
change its internal resistance in response to the tem-
peratures it monitors. The A/C-heater control is con-
nected to the sensor through a sensor ground circuit
and a sensor signal circuit. As the evaporator tem-
perature increases, the resistance of the sensor
decreases and the voltage monitored by the A/C-
heater control decreases. The A/C-heater control uses
this monitored voltage reading to an indication of the
evaporator temperature. The A/C-heater control is
programmed to respond to this input by cycling the
A/C compressor clutch off if the evaporator tempera-
ture sensor reads between 1É C (33É F) and 3.5É C
(38É F) to protect the A/C evaporator from freezing.
Fig. 17 A/C-Heater Control
Fig. 18 Sensor-Evaporator Temperature
1 - EVAPORATOR TEMPERATUE SENSOR
2 - A/C EVAPORATOR
3 - HVAC HOUSING
4 - WIRE CONNECTOR
VACONTROLS-FRONT 24 - 19

INSTALLATION
NOTE: Replacement of the PTFE thread sealing
tape is required anytime the rear A/C low pressure
switch is removed from the rear suction line line.
Failure to replace the sealing tape could result in a
rear refrigerant system leak.
(1) Remove the tape or plug from the rear suction
line fitting.
(2) Install PTFE thread sealing tape onto the rear
A/C low pressure switch and install the switch onto
the rear suction line. Tightened the A/C low pressure
switch to 10 N´m (88 in. lbs.).
(3) Connect the wiring harness connector to the
rear A/C low pressure switch.
(4) Install new insulating tape around the rear A/C
low pressure switch area.
(5) Reconnect the negative battery cable.
(6) Evacuate the rear refrigerant system (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).
(7) Charge the rear refrigerant system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).
(8) Install the cover onto the rear A/C evaporator
housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - INSTALLATION).
BLOWER MOTOR RELAY
DESCRIPTION
The three rear blower motor relays used for the
rear A/C system are International Standards Organi-
zation (ISO)-type relays (Fig. 11). Relays conforming
to the ISO specifications have common physical
dimensions, current capacities, terminal functions
and patterns. The rear blower motor relays are elec-
tromechanical devices that switches fused battery
current directly to the rear blower motors. The rear
blower motor relays are energized when the relay
coils are provided battery current by the rear blower
motor switch (Refer to 24 - HEATING & AIR CON-
DITIONING/CONTROLS/BLOWER MOTOR
SWITCH - DESCRIPTION).
The rear blower motor relays are located in the
relay block in the rear A/C evaporator housing.
OPERATION
The three ISO-standard rear blower motor relays
are electromechanical switches that uses a low cur-
rent input from the rear blower motor switch to con-
trol the high current output to the rear blower
motors. The movable, common feed relay contact is
held against the fixed, normally closed relay contact
by spring pressure. When the electromagnetic relay
coil is energized, it draws the movable common feed
relay contact away from the fixed, normally closed
relay contact and, holds it against the fixed, normally
open relay contact. This action allows high current to
flow to the rear blower motors.
When the relay coil is de-energized, spring pres-
sure returns the movable relay contact back against
the fixed, normally closed contact point. The resistor
Fig. 10 Rear A/C Low Pressure Switch
1 - INSULATING TAPE
2 - REAR A/C EVAPORATOR HOUSING
3 - WIRE HARNESS CONNECTOR
4 - REAR A/C LOW PRESSURE SWITCH
5 - REAR SUCTION LINE FITTING
Fig. 11 Rear Blower Motor Relays
1 - STANDARD ISO RELAY
2 - TERMINAL PATTERN
VACONTROLS - REAR 24 - 33

INSTALLATION
NOTE: Be certain to add refrigerant oil if the rear
A/C condenser is being replaced. The refrigerant oil
must be drained from the old condenser and mea-
sured to determine the amount of refrigerant oil to
add to the new condenser. Use only refrigerant oil
of the type recommended for the rear A/C compres-
sor in the vehicle.
(1) If the rear A/C condenser is being replaced,
install the correct amount and type of refrigerant oil
into the new rear A/C condenser. Drain the old con-
denser and measure the refrigerant oil. Fill the new
condenser with the same amount of new refrigerant
oil that was drained out of the old condenser.
(2) Install new body sealant and any removed
shims onto the top of the roof panel.
(3) With help from an assistant, position the rear
A/C condenser housing onto the top of the roof panel.
(4) Install the eight nuts and washers that secure
the rear A/C condenser housing to the roof panel.
Tighten the nuts to 25 N´m (18 ft. lbs.).
(5) Remove the tape or plugs from the rear liquid
line fitting and rear refrigerant reservoir port.
(6) Lubricate a new O-ring seal with clean refrig-
erant oil and install it onto the rear liquid line fit-
ting. Use only the specified O-ring seal as it is madeof a special material for the R-134a system. Use only
refrigerant oil of the type recommended for the rear
A/C compressor in the vehicle.
(7) Connect the rear liquid line to the rear refrig-
erant reservoir outlet. Tighten the liquid line nut to
35 N´m (26 ft. lbs.).
(8) Remove the tape or plugs from the rear dis-
charge line fitting and rear condenser port.
(9) Lubricate a new O-ring seal with clean refrig-
erant oil and install it onto the rear discharge line
fitting. Use only the specified O-ring seal as it is
made of a special material for the R-134a system.
Use only refrigerant oil of the type recommended for
the rear A/C compressor in the vehicle.
(10) Connect the rear discharge line to the rear
A/C condenser. Tighten the discharge line nut to 35
N´m (26 ft. lbs.).
(11) Install the bracket and screw that secures the
rear discharge line to the right side of the rear con-
denser housing. Tighten the screw securely.
(12) Connect the rear A/C wire harness to the rear
blower motor suppression filter and to the rear A/C
high pressure switch.
(13) Install new retaining straps to secure the rear
A/C wire harness to the rear liquid line.
(14) Install a new rear receiver/drier (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/
REAR RECEIVER/DRIER - INSTALLATION).
Fig. 2 Rear A/C Condenser Housing
1 - REAR A/C CONDENSER HOUSING
2 - LIQUID LINE
3 - REAR REFRIGERANT RESERVOIR
4 - REAR A/C HIGH PRESSURE SWITCH
5 - REAR CONDENSER OUTLET TUBE6 - SUCTION LINE
7 - NUT AND WASHER (8)
8 - REAR A/C WIRE HARNESS
9 - REAR BLOWER MOTOR SUPPRESSION FILTER
24 - 54 DISTRIBUTION - REARVA

INSTALLATION
NOTE: Be certain to add refrigerant oil if the rear
A/C evaporator is being replaced. The refrigerant oil
must be drained from the old evaporator and mea-
sured to determine the amount of refrigerant oil to
add to the new evaporator. Use only refrigerant oil
of the type recommended for the rear A/C compres-
sor in the vehicle.
(1) If the rear A/C evaporator is being replaced,
install the correct amount and type of refrigerant oil
into the new rear A/C evaporator. Drain the old evap-
orator and measure the refrigerant oil. Fill the new
evaporator with the same amount of new refrigerant
oil that was drained out of the old evaporator.
(2) With help from an assistant, position and sup-
port the rear A/C evaporator housing into the vehicle.
(3) Inspect the four rubber damping washers for
correct sealing. Replace the washers as required.
CAUTION: Be sure to install the rear A/C system
ground lead with one of the rear evaporator hous-
ing retaining bolts. Failure to correctly install theground lead could result in improper operation or
possible damage to the rear A/C system.
(4) Position the ground lead to the rear A/C evap-
orator housing and install the four bolts and washers
and four damping washers that secure the evapora-
tor housing to the roof panel. Tighten the bolts to 25
N´m (18 ft. lbs.).
(5) Install the nine screws that secure the rear A/C
evaporator housing to the roof panel. Tighten the
screws to 5 N´m (45 in. lbs.).
(6) Unplug and connect the two rear evaporator
drain hoses.
(7) Remove the tape or plugs from the refrigerant
line fittings and the rear expansion valve and evap-
orator tube ports.
(8) Lubricate a new O-ring seal with clean refrig-
erant oil and install it onto the rear liquid line fit-
ting. Use only the specified O-ring seal as it is made
of a special material for the R-134a system. Use only
refrigerant oil of the type recommended for the rear
A/C compressor in the vehicle.
(9) Connect the rear liquid line to the rear A/C
expansion valve. Tighten the liquid line nut to 35
N´m (26 ft. lbs.).
Fig. 5 Rear A/C Evaporator Housing
1 - REAR A/C EVAPORATOR HOUSING
2 - REAR A/C WIRE HARNESS
3 - REAR BODY WIRE HARNESS
4 - NUT
5 - POSITIVE WIRE LEAD
6 - GROUND LEAD
7 - GROMMET
8 - SEALING WASHER (4)
9 - BOLT AND WASHER (4)10 - REAR EVAPORATOR DRAIN HOSES
11 - SCREW (9)
12 - REAR DOME LAMP HARNESS
13 - REAR A/C EVAPANSION VALVE
14 - REAR LIQUID LINE FITTING
15 - REAR A/C EVAPORATOR OUTLET TUBE
16 - REAR SUCTION LINE FITTING
17 - INSULATING TAPE
VADISTRIBUTION - REAR 24 - 57

(10) Lubricate a new O-ring seal with clean refrig-
erant oil and install it onto the rear suction line fit-
ting. Use only the specified O-ring seal as it is made
of a special material for the R-134a system. Use only
refrigerant oil of the type recommended for the rear
A/C compressor in the vehicle.
(11) Connect the rear suction line to the rear evap-
orator outlet tube. Tighten the suction line nut to 35
N´m (26 ft. lbs.).
(12) Install new insulating tape around the rear
evaporator connections.
(13) Install the positive wire lead onto the rear
A/C system terminal block and install the retaining
nut. Tighten the nut securely.
(14) Reposition the rear dome lamp harness and
install the retaining straps that secure the harness
to the rear A/C evaporator housing.
(15) Connect the rear A/C wire harness connector
to the rear body wire harness.
(16) Route the rear A/C wire harness up through
the roof panel and install the grommet.
(17) Connect the rear A/C wire harness to the rear
condenser fan suppression filter and the rear A/C
high pressure switch and install the retaining straps
that secure the wire harness to the rear liquid line.
(18) Reconnect the negative battery cable.
(19) Evacuate the rear refrigerant system (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).
(20) Charge the rear refrigerant system (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).
(21) Install the cover onto the rear A/C evaporator
housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - INSTALLATION).
(22) Install the cover onto the rear A/C condenser
housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C CON-
DENSER COVER - INSTALLATION).
AIR FILTER
REMOVAL
(1) Unlock the eight quick-release fasteners by
turning them 90 degrees counter clockwise (Fig. 6).
(2) Remove the rear air inlet grate from the rear
A/C evaporator cover.
(3) Remove the rear particulate air filter by disen-
gaging the velcro-type retainers.
(4) Carefully clean the rear particulate air filter
using compressed air.
INSTALLATION
NOTE: Replace the rear particulate air filter if it is
heavily soiled or damaged.
(1) Position the rear particulate air filter and
engage the velcro-type retainers.
(2) Install the rear air inlet grate onto the rear
A/C evaporator cover.
(3) Lock the eight quick-release fasteners by turn-
ing them 90 degrees clockwise.
BLOWER MOTOR
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the cover from the rear A/C evaporator
housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C EVAPORA-
TOR COVER-REAR - REMOVAL).
(3) Disconnect the wire harness connectors from
the rear blower motor suppression filter and from the
rear blower motor being serviced and remove the
suppression filter (Fig. 7).
(4) Remove the body sealer from around the rear
blower motor area being serviced.
(5) Remove the screws that secure each rear
blower motor to the rear evaporator housing and
remove blower motor.
Fig. 6 Rear Particulate Air Filter
1 - QUICK-RELEASE FASTENER (8)
2 - REAR A/C EVAPORATOR COVER
3 - REAR PARTICULATE AIR FILTER
4 - REAR AIR INLET GRATE
24 - 58 DISTRIBUTION - REARVA

(12)EXAMPLE:The ambient temperature is 21É
C (70É F). The evaporator inlet tube temperature is
12É C (54É F) and the evaporator outlet tube temper-
ature is 10É C (50É F). Subtract the inlet tube tem-
perature from the outlet tube temperature. The
difference is -2É C (-4É F). With a -2É C (-4É F) tem-
perature differential at 21É C (70É F) ambient tem-
perature, the system is fully charged.
(13) Add enough refrigerant to bring the refriger-
ant system up to a full charge.
(14) Remove the jumper wire from the low pres-
sure cycling clutch switch wire harness connector
and plug the connector back into the switch.
A / C COMPRESSOR
DESCRIPTION
The standard front A/C system uses a Denso
7SBU16C seven cylinder, variable displacement
swash plate-type A/C compressor (Fig. 2). This A/C
compressor has a volume control which is regulated
by an internal control valve and has both the suction
and discharge ports located at the rear of the com-
pressor.
The optional independant Konvekta rear A/C sys-
tem uses theDenso 10S17C ten cylinder, double-act-
ing swash plate-type A/C compressor (Fig. 3). This
A/C compressor has a fixed displacement of 170 cubic
centimeters (10.374 cubic inches), and has both the
suction and discharge ports located on the cylinder
head at the rear of the compressor.A label identifying the use of R-134a refrigerant is
located on both A/C compressors.
OPERATION
The A/C compressor is driven by the engine
through an electric clutch, drive pulley and belt
arrangement. The A/C compressor is lubricated by
refrigerant oil that is circulated throughout the
refrigerant system with the refrigerant.
The A/C compressor draws in low-pressure refrig-
erant vapor from the A/C evaporator through its suc-
tion port. It then compresses the refrigerant into a
high-pressure, high-temperature refrigerant vapor,
which is then pumped to the A/C condenser through
the compressor discharge port.
The A/C compressor cannot be repaired and, if
faulty or damaged, it must be replaced. The compres-
sor clutch, pulley and bearing assembly, and clutch
field coil are available for service. If an internal fail-
ure of the A/C compressor has occurred, the receiver/
drier must also be replaced.
DIAGNOSIS AND TESTING
A / C COMPRESSOR NOISE
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
Fig. 2 Denso 7SBU16C A/C Compressor
1 - A/C COMPRESSOR (DENSO 7SBU16C)
2 - SUCTION AND DISCHARGE PORT
3 - INTERNAL CONTROL VALVE
Fig. 3 Denso 10S17C A/C Compressor
1 - A/C COMPRESSOR (DENSO 10S17C)
2 - SUCTION AND DISCHARGE PORT
3 - CYLINDER HEAD
24 - 66 PLUMBINGVA