2005 MERCEDES-BENZ SPRINTER Service Repair Manual

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS.......................1
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
OPERATION - HEATER AND AIR
CONDITIONER........................2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FUNCTION
TEST................................3
DIAGNOSIS AND TESTING - A/C
PERFORMANCE TEST..................3DIAGNOSIS AND TESTING - HEATER
PERFORMANCE.......................4
SPECIFICATIONS
A/C SYSTEM..........................5
CONTROLS - FRONT......................8
CONTROLS - REAR......................22
DISTRIBUTION - FRONT...................31
DISTRIBUTION - REAR....................39
PLUMBING.............................43
CABIN HEATER.........................72
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the heating-
air conditioning system, the engine cooling system
must be properly maintained. The use of a bug
screen is not recommended. Any obstructions in front
of the radiator or condenser will reduce the perfor-
mance of the air conditioning and engine cooling sys-
tems.
The engine cooling system includes the radiator,
thermostat, heater core, heater hoses and the engine
coolant pump. Refer to Cooling for more information
before opening or attempting any service to the
engine cooling system.
DESCRIPTION - HEATER AND AIR
CONDITIONER
A automatic temperature control (ATC) single zone
type heating-air conditioning system is standard
equipment on this model. A manually controlled rear
air conditioning system is available as a factory-in-
stalled option.
All vehicles are equipped with a common ventila-
tion housing (Fig. 1) located in the engine compart-
ment which includes:
²blower motor
²blower motor resistor block²recirculation door and actuator
All vehicles are also equipped with a common
heater housing mounted under the instrument panel
which includes:
²heater core
²evaporator core
²evaporator temperature sensor
Fig. 1 Ventilation Housing
1 - NUT (5)
2 - WASHER (5)
3 - VENTILATION HOUSING
4 - HOUSING COVER
VAHEATING & AIR CONDITIONING 24 - 1

²expansion valve
²air outlet temperature sensor
²mode doors
Vehicles equipped with the factory-installed
optional rear air conditioning system (Fig. 2) use a
common roof mounted assembly which includes:
²solenoid valve
²evaporator core
²evaporator temperature sensor
²expansion valve
²blower motor and wheel assembly
A heater booster is used to aid in warming the
engine coolant. The heater booster system can be
switched on while the vehicle is being driven to help
the engine reach its normal operating temperature
quickly and will help aid in heating up the air within
the passenger compartment quickly when requested
by the operator (Fig. 3).
OPERATION - HEATER AND AIR CONDITIONER
Outside air enters the vehicle through the hood
opening at the base of the windshield, and passesthrough the ventilation housing located in the engine
compartment into the heater housing located behind
the instrument panel. Air flow velocity is adjusted
with the blower motor speed selector thumbwheel on
the A/C-heater control. The air intake openings must
be kept free of snow, ice, leaves, and other obstruc-
tions for the HVAC system to receive a sufficient vol-
ume of outside air.
The automatic temperature control (ATC) system
controls interior temperature by taking actual values
from the temperature sensors and the CAN bus and
comparing them to the nominal value of the temper-
ature control switch. The electric pulsed heater valve
is then energized depending on the requested quan-
tity of heat and an electrically-operated water pump
gives a nearly constant water flow for exact temper-
ature regulation. If the solenoid is not energized, the
coolant circuit to the heat exchanger is fully open. To
control the temperature the solenoid valve is pulsed
by the ATC in periods of four seconds.
The mode control knob on the A/C-heater control is
used to direct the conditioned air flow to the selected
air outlets. The mode control knob operates the mode
doors by cables connected to the mode doors.
When the outside air contains smoke, oders, high
humidity, or if rapid cooling is desired, interior air
can by recirculated by selecting the Recirculation
Mode with the mode control knob. The mode control
knob operates the recirculation door through use of a
vaccum actuator. When the Recirculation Mode is
selected, the recirculation door is closed to prevent
outside air from entering the passenger compart-
ment.
Fig. 2 Heater Housing
1 - SCREW (12)
2 - HEATER HOUSING COVER
3 - EVAPORATOR
4 - EVAPORATOR O-RING SEAL (2)
4 - EVAPORATOR GASKET
6 - VENTILATION HOUSING GASKET
7 - HEATER HOUSING
8 - WIRING HARNESS
9 - BOLT (3)
10 - HEATER CORE
11 - HEATER CORE TUBE ASSEMBLY
12 - HEATER CORE TUBE GASKET
13 - HEATER CORE TUBE O-RING SEAL (2)
Fig. 3 Heater Booster
24 - 2 HEATING & AIR CONDITIONINGVA
HEATING & AIR CONDITIONING (Continued)

To maintain minimum evaporator temperature and
prevent evaporator freezing, an evaporator tempera-
ture sensor is used.
Vehicles equipped with the available rear A/C sys-
tem have an individual temperature control and
blower motor speed switches. When the rear A/C sys-
tem is turned on, a solenoid valve opens the rear
refrigerant circuit and activates the blower motor for
the rear evaporator. The circulated internal air tem-
perature is measured by a temperature sensor and
the temperature value is compared within the rear
A/C control module to an adjusted value at the tem-
perature control switch. To prevent icing of the rear
evaporator, the temperature switch cuts off the flow
of refrigerant through the rear A/C circuit by de-en-
ergizing the solenoid valve.
The front and rear A/C systems are designed for
the use of non-CFC, R-134a refrigerant only. Both
the front and rear systems use an expansion valve to
meter refrigerant flow to the evaporator.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FUNCTION TEST
The ATC system can perform an self-test, which
can be activated by the DRBIIItscan tool to confirm
that the air conditioning system is performing satis-
factorily. This test provides a quick confirmation of
heater - air conditioning system performance to the
service technician. Refer to Body Diagnostic Proce-
dures for the appropriate diagnostic information.
DIAGNOSIS AND TESTING - A/C
PERFORMANCE TEST
The air conditioning system is designed to provide
the passenger compartment with low temperature
and low specific humidity air. The evaporator, located
in the heater housing on the dash panel below the
instrument panel, is cooled to temperatures near the
freezing point. As warm damp air passes through the
cooled evaporator, the air transfers its heat to the
refrigerant in the evaporator and the moisture in the
air condenses on the evaporator fins. During periods
of high heat and humidity, an air conditioning sys-
tem will be more effective in the Recirculation Mode.
With the system in the Recirculation Mode, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, the air conditioning system performance
levels improve.
Humidity has an important bearing on the temper-
ature of the air delivered to the interior of the vehi-
cle. It is important to understand the effect that
humidity has on the performance of the air condition-
ing system. When humidity is high, the evaporatorhas to perform a double duty. It must lower the air
temperature, and it must lower the temperature of
the moisture in the air that condenses on the evapo-
rator fins. Condensing the moisture in the air trans-
fers heat energy into the evaporator fins and tubing.
This reduces the amount of heat the evaporator can
absorb from the air. High humidity greatly reduces
the ability of the evaporator to lower the temperature
of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Remov-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from their
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
NOTE: Very specific instructions and conditions
pertain to this procedure which are significantly dif-
ferent than procedures used in other vehicle appli-
cations. Follow each step in the order they are
presented. Do not skip steps or change conditions
from those stated or results will be adversely
affected and invalid.
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
(1) Place the vehicle in the shade with all widows
open.
(2) Turn the temperature control to cold.
(3) Select Fresh Air, not Recirculate and open all
air conditioning duct louvers.
(4) Start the vehicle and allow it to idle.
(5) Turn the blower switch to the maximum blower
speed setting and allow to operate for a short period
of time before proceeding.
(6) Perform an outlet temperature test as follows:
a. Turn the blower switch to the lowest blower
speed setting.
b. Insert a thermometer into a center duct for at
least five minutes.
VAHEATING & AIR CONDITIONING 24 - 3
HEATING & AIR CONDITIONING (Continued)

c. With the engine running, duct temperature
should not be less than 2É C (35É F) or than 12É C
(54É F).
(7) If the compressor has not cycled off and the
duct temperature is less than 2É C (35É F) , check the
evaporator temperature sensor and circuit by per-
forming the ATC Function Test (Refer to 24 - HEAT-
ING & AIR CONDITIONING - DIAGNOSIS AND
TESTING).
(8) If duct output temperature is not within speci-
fications, check the refrigerant system for leaks and
proper refrigerant charge (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - DIAGNOSIS
AND TESTING) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE).
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, perform the
ATC Function Test using the DRBIIItand refer toCooling for the procedures to check the radiator cool-
ant level, serpentine drive belt tension, radiator air
flow and the radiator fan operation.
MAXIMUM HEATER OUTPUT
Engine coolant is provided to the heater core
through a heater valve and heater hose. With the
engine idling at normal operating temperature, set
the heater-A/C controls as follows:
²Temperature control in the full hot position
²Mode control in the floor heat position
²Blower motor control in the highest speed posi-
tion
Using a test thermometer, check the temperature
of the air being discharged at the floor outlets. Com-
pare the test thermometer reading to the Tempera-
ture Reference chart.
TEMPERATURE REFERENCE CHART
Ambient Temperature Minimum Floor Outlet Temperature
Celsius Fahreheit Celsius Fahreheit
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
If the floor outlet air temperature is insufficient,
check for a faulty heater valve (perform ATC Func-
tion Test) and verify that the cooling system is oper-
ating to specifications (Refer to 7 - COOLING/
ENGINE/COOLANT - DIAGNOSIS AND TESTING).
Both of the heater hoses should be HOT to the touch
(the coolant return heater hose should be slightly
cooler than the supply hose. If the coolant return
hose is much cooler than the supply hose, locate and
repair the engine coolant flow obstruction in the
heater system.
POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²Inoperative or stuck heater water valve.
²Plugged heater core.If proper coolant flow is verified, and heater floor
outlet air temperature is insufficient, a mechanical
problem may exist.
POSSIBLE LOCATIONS OR CAUSE OF
INSUFFICIENT HEAT
²An obstructed cowl air intake.
²Obstructed heater system outlets.
²Heater water valve not functioning properly.
TEMPERATURE CONTROL
If outlet air temperature cannot be adjusted with
the A/C-heater temperature control, one of the follow-
ing could require service:
²Faulty A/C-heater control switch.
²Faulty temperature sensor.
²Faulty A/C-heater control cable or actuator.
²Faulty A/C-heater control module.
24 - 4 HEATING & AIR CONDITIONINGVA
HEATING & AIR CONDITIONING (Continued)

SPECIFICATIONS
A/C SYSTEM
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood specifica-
tion label for the A/C unit.
SYSTEM SPECIFICATIONS
Item Description Notes
Compressor Nippondenso -
7SBU16CND-8 PAG oil
Low psi Control A/C Pressure
TransducerLiquid line
mounted -
opens below
152 kPa (22
psi) - resets
above 234 - 262
(34-38 psi)
Item Description Notes
High psi Control High Pressure
Relief ValveCompressor
mounted -
opens at a
discharge
pressure over
3445 04135 kPa
(500 - 600 psi)
Compressor
Clutch Coil
Draw2.0-3.7 amps
@ 11.5 - 12V
@ 21É C (70É
F)
Compressor
Clutch Air Gap0.5 - 0.88 mm
(0.020 - 0.035
in.)
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A/C Compressor bolts 20 15 Ð
A/C Compressor Shaft Bolt 17.5 Ð 155
Air Nozzle Reinforcing
Plate Screws2Ð 17
Air Outlet Screws 2 Ð 17
Auxiliary Fan Bracket
Screws5Ð 45
Auxiliary Fan Bracket Nuts 5 Ð 45
Blower Motor Screws 2 Ð 17
Condenser Screws 2 Ð 17
Defroster Duct Screws 2 Ð 17
Discharge Line to
Compressor Bolt23 17 Ð
Discharge Line to
Compressor Nut33 24 Ð
Heater-A/C Control Screws 2 Ð 17
Heater Core Tube to Heater
Core Bolts5Ð 45
Heater Housing Cover
Screws2Ð 17
Heater Housing to Dash
Panel Screws4.5 Ð 40
Electric Coolant Pump
Bracket Bolts5Ð 45
VAHEATING & AIR CONDITIONING 24 - 5
HEATING & AIR CONDITIONING (Continued)

Description N´m Ft. Lbs. In. Lbs.
Expansion Valve to
Evaporator Tube Tapping
Plate Bolts5Ð 45
Floor Duct Screws 2 Ð 17
Heater Core Tube Bolts 5 Ð 45
Heater Water Valve Bracket
Bolts5Ð 45
Instrument Panel Duct
Screws2Ð 17
Instrument Panel End
Cover Screws2Ð 17
Intermediate Suction Line
to Front Suction Line
Tapping Plate Bolt10 Ð 89
Liquid Line to Condenser
Nut17 12 Ð
Liquid Line to Reciever-
Drier Bolt7Ð 62
Rear A/C Control Module
Screws2Ð 17
Rear A/C Solenoid Valve
Screws10 Ð 89
Rear A/C Solenoid Valve
Refrigerant Line Nuts16 Ð 142
Rear A/C Blower Motor
Screws5Ð 45
Rear A/C Refrigerant Line
Retaining Block Bolts5Ð 45
Rear A/C Suction Line to
Front Suction Line Tapping
Plate Bolt5Ð 45
Rear Condensation Trap
Screws2Ð 17
Rear Evaporator Housing
Bolts20 15 177
Rear Evaporator Housing
Screw5Ð 45
Rear Evaporator Panel
Screws2Ð 17
Rear Expansion Valve to
Evaporator Tapping Plate
Bolts5Ð 45
Rear Liquid Line to
Expansion and Solenoid
Valve Nuts16 Ð 142
Rear Liquid Line to
Intermediate Liquid Line
Nut16 Ð 142
24 - 6 HEATING & AIR CONDITIONINGVA
HEATING & AIR CONDITIONING (Continued)

Description N´m Ft. Lbs. In. Lbs.
Rear Liquid Line to
Sidewall Liquid Line Nut16 Ð 142
Rear Suction Line to
Intermediate Suction Line
Nut30 22 Ð
Rear Suction Line to
Sidewall Suction Line Nut30 22 Ð
Rear Suction Line to
Solenoid Valve10 Ð 89
Recirculation Door Actuator
Screws2Ð 17
Suction Line Routing Clip
Nut5Ð 45
Suction Line to Compressor
Bolt23 17 Ð
Suction Line to Front
Expansion Valve Nut10 Ð 89
Supplemental Heater Air
Intake Pipe Screws7Ð 62
Supplemental Heater M6
Fasteners7Ð 62
Supplemental Heater M8
Fasteners23 17 Ð
Supplemental Heater Seat
to Mounting Flange Nut60 44 Ð
Terminal Block to
Evaporator Bolts5Ð 45
Ventilation Housing to Dash
Panel Nuts5Ð 45
VAHEATING & AIR CONDITIONING 24 - 7
HEATING & AIR CONDITIONING (Continued)

CONTROLS - FRONT
TABLE OF CONTENTS
page page
A/C COMPRESSOR CLUTCH
DESCRIPTION..........................8
OPERATION............................8
STANDARD PROCEDURE
STANDARD PROCEDURE - COMPRESSOR
CLUTCH AIR GAP......................9
STANDARD PROCEDURE - COMPRESSOR
CLUTCH BREAK-IN.....................9
REMOVAL.............................9
INSPECTION - COMPRESSOR CLUTCH/COIL . 10
INSTALLATION.........................11
A/C COMPRESSOR CLUTCH COIL
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL........................12
A/C HEATER CONTROL
DESCRIPTION.........................12
OPERATION...........................12
REMOVAL.............................12
INSTALLATION.........................13
A/C PRESSURE TRANSDUCER
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING - A/C PRESSURE
TRANSDUCER.......................13
REMOVAL.............................14
INSTALLATION.........................14
AIR OUTLET TEMPERATURE SENSOR
DESCRIPTION.........................14
OPERATION...........................15
REMOVAL.............................15
INSTALLATION.........................15
AMBIENT TEMPERATURE SENSOR
DESCRIPTION.........................15
OPERATION...........................15REMOVAL.............................15
INSTALLATION.........................16
BLOWER MOTOR RESISTOR BLOCK
DESCRIPTION.........................16
OPERATION...........................16
DIAGNOSIS AND TESTING - BLOWER
MOTOR RESISTOR BLOCK..............16
REMOVAL.............................16
INSTALLATION.........................17
BLOWER MOTOR SWITCH
DESCRIPTION.........................17
OPERATION...........................17
DIAGNOSIS AND TESTING - BLOWER
MOTOR SWITCH......................17
REMOVAL.............................17
EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................17
OPERATION...........................18
REMOVAL.............................18
INSTALLATION.........................18
IN-CAR TEMPERATURE SENSOR
DESCRIPTION.........................19
OPERATION...........................19
DIAGNOSIS AND TESTING................19
REMOVAL.............................19
MODE DOOR CABLES
REMOVAL.............................19
INSTALLATION.........................19
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................20
OPERATION...........................20
REMOVAL.............................21
INSTALLATION.........................21
A/C COMPRESSOR CLUTCH
DESCRIPTION
The compressor clutch assembly consists of a sta-
tionary electromagnetic coil, a hub bearing and pul-
ley assembly, and a clutch plate (Fig. 1). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is keyed to the compressor shaft and secured
with a bolt.
The compressor clutch plate and pully, or the clutch
coil are available for seperate service replacement.
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.
24 - 8 CONTROLS - FRONTVA