2006 MERCEDES-BENZ SPRINTER cooling

(5) Install the two A/C-heater control retaining
screws. Tighten the screws to 2 N´m (17 in. lbs.).
(6) Install the center bezel onto the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(7) Reconnect the negative battery cable.
A / C PRESSURE TRANS-
DUCER
DESCRIPTION
The A/C pressure transducer is installed on the liq-
uid line fitting located at the top of the receiver/drier
(Fig. 9). A rubber O-ring seals the connection
between the transducer and the fitting. Three termi-
nals within a molded plastic connector receptacle on
the top of the transducer connect it to the vehicle
electrical system through a wire lead and connector.
The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
OPERATION
The A/C pressure transducer monitors the pres-
sures in the high side of the refrigerant systemthrough its connection to a fitting on the liquid line.
The transducer will change its internal resistance in
response to the pressures it monitors. The ATC con-
trol module provides a five volt reference signal and
monitors the output voltage of the transducer on the
transducer return circuit to determine refrigerant
pressure. The ATC module is preprogrammed to
respond to this and other sensor inputs by controlling
the operation of the air conditioning compressor
clutch and the auxiliary radiator cooling fan to help
optimize air conditioning system performance and to
protect the system components from damage. The
A/C pressure transducer input to the ATC module
also prevents the A/C compressor clutch from engag-
ing when the ambient temperature is below 0.556É C
(33É F) due to the pressure/temperature relationship
of the refrigerant.
The A/C pressure transducer is diagnosed by per-
forming the ATC Function Test using the DRBIIIt
scan tool. Refer to Body Diagnostic Procedures.
The A/C pressure transducer cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
DIAGNOSIS AND TESTING
A / C PRESSURE TRANSDUCER
The A/C pressure transducer is tested using a
DRBIIItscan tool. Refer to Body Diagnostic Proce-
dures. Before testing the A/C pressure transducer, be
certain that the transducer wire harness connections
are clean of corrosion and properly connected. For
the air conditioning system to operate, an A/C pres-
sure transducer voltage reading between 0.7 and 4.56
volts is required. Voltage outside this range indicate
a low or high refrigerant system pressure condition
to the ATC control module. The control module is
programmed to respond to a low or high refrigerant
system pressure by suppressing operation of the com-
pressor. Refer to the A/C Pressure Transducer Volt-
age chart for the possible condition indicated by the
transducer voltage readings.
Fig. 9 A/C Pressure Transducer
1 - A/C PRESSURE TRANSDUCER
2 - PIEZORESISTIVE ELEMENT
3 - WIRE CONNECTOR
24 - 14 CONTROLS-FRONTVA

INSTALLATION
(1) Position the rear A/C clutch relay into the
proper receptacle of the relay block located in the
rear A/C evaporator housing.
(2) Align the A/C clutch relay terminals with the
terminal cavities in the relay block receptacle and
push down firmly on the relay until the terminals
are fully seated.
(3) Install the rear air filter (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION -
REAR/AIR FILTER - INSTALLATION).
(4) Reconnect the negative battery cable.
A / C CONDENSER FAN RELAY
DESCRIPTION
The rear A/C condenser fan relay for the rear A/C
system is an International Standards Organization
(ISO)-type relay (Fig. 3). Relays conforming to the
ISO specifications have common physical dimensions,
current capacities, terminal functions and patterns.
The rear A/C condenser fan relay is an electrome-
chanical device that uses a low current input to con-
trol the high current output to the A/C condenser fan
for the rear heating-A/C system.
The rear A/C condenser fan relay is located in the
relay block in the rear A/C evaporator housing.
OPERATION
The ISO-standard rear A/C condenser fan relay is
an electromechanical switch that uses a low current
input from the rear A/C control module to control the
high current output to the rear A/C condenser cooling
fan. The movable, common feed relay contact is held
against the fixed, normally closed relay contact by
spring pressure. When the electromagnetic relay coil
Fig. 2 Rear A/C Clutch Relay
1 - REAR A/C EVAPORATOR HOUSING
2 - BLOWER MOTOR RELAY K204
3 - BLOWER MOTOR RELAY K2034 - BLOWER MOTOR RELAY K201
5 - REAR CONDENSER FAN RELAY K205
6 - REAR COMPRESSOR RELAY K206
Fig. 3 Rear A/C Condenser Fan Relay
1 - STANDARD ISO RELAY
2 - TERMINAL PATTERN
24 - 26 CONTROLS - REARVA

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 electric cooling fan motor.
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
or diode is connected in parallel with the relay coil,
and helps to dissipate voltage spikes and electromag-
netic interference that can be generated as the elec-
tromagnetic field of the relay coil collapses.
The rear A/C condenser fan relay terminals are
connected to the vehicle electrical system through a
receptacle in the relay block located in the rear A/C
evaporator housing.
The rear A/C condenser fan relay cannot be
repaired and, if faulty or damaged, it must be
replaced. Refer to the appropriate wiring information
for diagnosis and testing of the ISO-standard relay
and for complete HVAC wiring diagrams.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the air filter from the rear A/C evapo-
rator housing (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION - REAR/AIR FILTER -
REMOVAL).
(3) Reach up into the rear A/C evaporator housing
and remove the rear A/C condenser fan relay from
the relay block (Fig. 4).
VACONTROLS - REAR 24 - 27

INSTALLATION
(1) Position the rear A/C control module to the
rear A/C evaporator housing.
(2) Install the two screws that secure the rear A/C
control module to the rear A/C evaporator housing.
Tighten the screws to 2 N´m (17 in. lbs.).
(3) Connect the wire harness connector to the rear
A/C control module.
(4) Install the rear air filter (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION -
REAR/AIR FILTER - INSTALLATION).
(5) Reconnect the negative battery cable.
A / C HIGH PRESSURE
SWITCH
DESCRIPTION
The rear A/C high pressure switch provides a sig-
nal to the rear A/C control module to control rear A/C
compressor clutch engagement/disengagement and,
control rear A/C condenser cooling fan operation (Fig.
7). The rear A/C control module will disengage the
rear A/C clutch if the rear refrigerant system pres-
sure exceeds approximately 2551 kPa (370 psi).
The rear A/C high pressure switch is mounted on a
fitting located on the inlet tube of the rear A/C con-
denser.The rear refrigerant system must be discharged
prior to removing the rear A/C high pressure
switch.
OPERATION
The contacts in the rear A/C high pressure switch
open and close causing the rear A/C control module
to turn the rear A/C clutch on and off. This prevents
Fig. 6 Rear A/C Control Module
1 - REAR A/C EVAPORATOR HOUSING
2 - REAR A/C CONTROL MODULE3 - WIRE HARNESS CONNECTOR
4 - SCREW (2)
Fig. 7 Rear A/C High Pressure Switch
1 - REAR PRESSURE SWITCH
2 - WIRE CONNECTOR
24 - 30 CONTROLS - REARVA

rear A/C compressor operation when the rear dis-
charge line pressure approaches high levels, and also
reduces electrical surging from rear A/C clutch
engagement.
The rear A/C high pressure switch controls rear
A/C condenser cooling fan operation by monitoring
the rear discharge line pressure. When the rear dis-
charge pressure rises above approximately 1900 to
2200 kPa (280 to 320 psi) the rear A/C condenser
cooling fan will turn on. The rear condenser cooling
fan will turn off when the rear discharge pressure
drops to approximately 1600 kPa (235 psi).
The rear A/C high pressure switch contacts open
when the rear discharge line pressure rises above
approximately 3100 to 3375 kPa (450 to 490 psi). The
rear A/C high pressure switch contacts close when
the rear discharge line pressure drops to approxi-
mately 1860 to 2275 kPa (270 to 330 psi).
The rear A/C high pressure switch is factory-cali-
brated and cannot be adjusted or repaired and, if
faulty or damaged, it must be replaced. Refer to the
appropriate wiring information for complete HVAC
wiring diagrams.
REMOVAL
WARNING: Refer to the applicable warnings and
cautions for this system before performing the fol-
lowing operation (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNINGS) and (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTIONS). Failure to follow the warnings and cau-
tions could result in possible personal injury or
death.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the air filter from the rear A/C evapo-
rator housing (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION - REAR/AIR FILTER -
REMOVAL).
(3) Recover the refrigerant from the rear refriger-
ant system (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY).
(4) Remove the cover from the rear A/C condenser
housing (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION - REAR/A/C CON-
DENSER COVER - REMOVAL).
(5) Disconnect the wire harness connector from the
rear A/C high pressure switch (Fig. 8).
(6) Remove the rear A/C high pressure switch and
install a plug into, or tape over the opened rear dis-
charge line fitting.
INSTALLATION
NOTE: Replacement of the PTFE thread sealing
tape is required anytime the rear A/C high pressure
switch is removed from the rear discharge line. Fail-
ure to replace the sealing tape could result in a rear
refrigerant system leak.
(1) Remove the tape or plug from the rear dis-
charge line fitting.
(2) Install PTFE thread sealing tape onto the rear
A/C high pressure switch and install the switch onto
the rear discharge line. Tightened the A/C high pres-
sure switch to 10 N´m (88 in. lbs.).
(3) Connect the wiring harness connector to the
rear A/C high pressure switch.
(4) Reconnect the negative battery cable.
(5) Evacuate the rear refrigerant system (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING
- STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).
(6) Charge the rear refrigerant system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).
(7) Install the rear air filter (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION -
REAR/AIR FILTER - INSTALLATION).
(8) 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).
Fig. 8 Rear A/C High Pressure Switch
1 - REAR A/C CONDENSER
2 - WIRE HARNESS CONNECTOR
3 - REAR A/C HIGH PRESSURE SWITCH
4 - REAR DISCHARGE LINE FITTING
VACONTROLS - REAR 24 - 31

INSTALLATION
(1) Position the rear evaporator temperature sen-
sor to the rear A/C evaporator housing.
(2) Install the two screws that secure the rear
evaporator temperature sensor to the rear A/C evap-
orator housing. Tighten the screws to 2 N´m (17 in.
lbs.).
(3) Install the sensor probe into the rear A/C evap-
orator.
(4) Connect the two wire harness connectors to the
rear evaporator temperature sensor.
(5) Install the rear air filter (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION -
REAR/AIR FILTER - INSTALLATION).
(6) Reconnect the negative battery cable.
TEMPERATURE CONTROL
DESCRIPTION
The temperature control for the optional rear A/C
system is a thumbwheel-type control mounted in the
switch panel on the instrument panel (Fig. 17). The
rear A/C temperature control allows the selection of
four temperature settings when the rear A/C blower
motor is activated.OPERATION
With the front A/C switch and rear blower motor
activated, the rear A/C output temperature can be
selected by rotating the thumbwheel control upwards
(increase cooling) or downwards (decrease cooling).
Depending on the rear A/C temperature control posi-
tion, a temperature command signal is sent to the
Fig. 16 Rear Evaporator Temperature Sensor
1 - REAR A/C EVAPORATOR HOUSING
2 - SCREWS (2)
3 - REAR EVAPORATOR SENSOR SWITCH UNIT4 - WIRE HARNESS CONNECTORS
5 - REAR EVAPORATOR SENSOR PROBE
Fig. 17 Rear A/C Temperature Control
24 - 38 CONTROLS - REARVA

(5) Remove the shift mechanism (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
NAG1/SHIFT MECHANISM - REMOVAL).
(6) Remove center floor distribution duct from the
heater housing.
INSTALLATION
(1) Install the center floor distribution duct onto
the heater housing.
(2) Install the shift mechanism (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
NAG1/SHIFT MECHANISM - INSTALLATION).
(3) Install the left and right floor distribution
ducts onto the center floor distribution duct.
(4) Install the left and right floor distribution duct
retaining screws to the instrument panel support.
Tighten the screws to 2 N´m (17 in. lbs.).
(5) Install the defroster ducts (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/DE-
FROSTER DUCTS - INSTALLATION).
(6) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
HVAC HOUSING
REMOVAL
WARNING: To avoid personal injury or death, on
vehicles equipped with airbags, disable the supple-
mental restraint system before attempting any
steering wheel, steering column, airbag, seat belt
tensioner, impact sensor, or instrument panel com-ponent diagnosis or service. Disconnect and isolate
the battery negative (ground) cable, then wait two
minutes for the system capacitor to discharge
before performing further diagnosis or service. This
is the only sure way to disable the supplemental
restraint system. Failure to take the proper precau-
tions could result in accidental airbag deployment.
WARNING: Refer to the applicable warnings and
cautions for this system before performing the fol-
lowing operation (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNINGS) and (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTIONS). Failure to follow the warnings and cau-
tions could result in possible personal injury or
death.
NOTE: The HVAC housing must be removed from
the vehicle and the two halves of the housing sep-
arated for service access of the heater core, A/C
evaporator and each of the various mode doors.
(1) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT SYSTEM RECOVERY)
(2) Partially drain the engine cooling system
(Refer to 7 - COOLING/ENGINE/COOLANT - STAN-
DARD PROCEDURE - DRAINING COOLING SYS-
TEM).
(3) Disconnect and isolate the negative battery
cable.
(4) Remove the air cleaner housing (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - REMOVAL).
(5) Remove the windshield washer reservoir (Refer
to 8 - ELECTRICAL/WIPERS/WASHERS/WASHER
RESERVOIR - REMOVAL).
(6) Remove the air filter from the ventilation hous-
ing (Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION/AIR FILTER - REMOVAL).
(7) Disconnect the wire harness and vacuum con-
nectors from the recirculation door actuator (Refer to
24 - HEATING & AIR CONDITIONING/CONTROLS/
RECIRCULATION DOOR ACTUATOR - REMOVAL).
(8) Disconnect the wire harness connector from the
blower motor resistor block (Refer to 24 - HEATING
& AIR CONDITIONING/CONTROLS/BLOWER
MOTOR RESISTOR BLOCK - REMOVAL).
(9) Disconnect the wire harness connector from the
blower motor (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION/BLOWER MOTOR -
REMOVAL).
(10) Remove the nuts and washers that secure the
ventilation housing to the body and remove the ven-
tilation housing from the vehicle (Fig. 7).
Fig. 6 Floor Distribution Duct, RH Shown, LH
Typical
1 - HEATER HOUSING
2 - SCREW (1)
3 - RH FLOOR DUCT
4 - CENTER FLOOR DUCT
24 - 48 DISTRIBUTION - FRONTVA

(12) Install the two bolts that secure the refriger-
ant line terminal block to the A/C evaporator.
Tighten the bolts to 5 N´m (45 in. lbs.).
(13) Unplug or remove the tape from the heater
core hoses and tubes.
(14) Connect the heater hoses to the heater core
tubes and install the heater hose clamps.
(15) Install the ventilation housing to the dash
panel.
(16) Install the nuts and washers that secure the
ventilation housing to the dash panel. Tighten the
nuts to 5 N´m (45 in. lbs.).
(17) Connect the wire harness connectors to the
blower motor, blower motor resistor block and the
recirculation door actuator.
(18) Connect the vacuum harness connector to the
recirculation door actuator.
(19) Install the air filter into the ventilation hous-
ing (Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION/AIR FILTER -
INSTALLATION).
(20) Install the windshield washer reservoir (Refer
to 8 - ELECTRICAL/WIPERS/WASHERS/WASHER
RESERVOIR - INSTALLATION).
(21) Install the air cleaner housing (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION).
(22) Reconnect the negative battery cable.
(23) If the heater core is being replaced, flush the
cooling system (Refer to 7 - COOLING - STANDARD
PROCEDURE - COOLING SYSTEM CLEANING/
REVERSE FLUSHING).
(24) Refill the engine cooling system (Refer to 7 -
COOLING/ENGINE/COOLANT - STANDARD PRO-
CEDURE - COOLANT SYSTEM FILL).
(25) Evacuate the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE).
(26) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE).
INSTRUMENT PANEL DUCTS
REMOVAL
(1) Remove the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - REMOVAL).
(2) Remove the defroster ducts (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
DEFROSTER DUCTS - REMOVAL).
(3) Remove the floor distribution ducts (Refer to 24
- HEATING & AIR CONDITIONING/DISTRIBU-
TION/FLOOR DISTRIBUTION DUCTS -
REMOVAL).(4) If removing the right instrument panel duct,
remove the passenger air bag module and bracket
(Refer to 8 - ELECTRICAL/RESTRAINTS/PASSEN-
GER AIRBAG - REMOVAL).
(5) Remove the screws that secure the left and/or
right instrument panel duct and remove the duct(s)
as required (Fig. 10).
INSTALLATION
(1) Connect the instrument panel duct(s) to the
heater housing as required.
(2) Install the instrument panel duct retaining
screws. Tighten the screws to 2 N´m (17 in. lbs.).
(3) If servicing the right instrument panel duct,
install the passenger air bag module and bracket
(Refer to 8 - ELECTRICAL/RESTRAINTS/PASSEN-
GER AIRBAG - INSTALLATION).
(4) Install the floor distribution ducts (Refer to 24
- HEATING & AIR CONDITIONING/DISTRIBU-
TION/FLOOR DISTRIBUTION DUCTS - INSTAL-
LATION).
(5) Install the defroster ducts (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/DE-
FROSTER DUCTS - INSTALLATION).
(6) Install the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - INSTALLATION).
Fig. 10 Instrument Panel Duct - RH Shown, LH
Typical
1 - RH DEFROSTER DUCT
2 - SCREW (2)
3 - RH INSTRUMENT PANEL DUCT
4 - RH FLOOR DISTRIBUTION DUCT
5 - CENTER FLOOR DISTRIBUTION DUCT
VADISTRIBUTION - FRONT 24 - 51