2005 MERCEDES-BENZ SPRINTER heating

Because the incoming air has a cooling effect, the
greater the amount of air that flows in, then the
higher the voltage of the heating resistor. The heat-
ing resistor is therefore a measure of mass of air
flowing past. If a temperature change occurs as a
result of a increase or reduction of air flow, the ECM
corrects the voltage at the heating resistor until the
temperature difference is again achieved. This con-
trol voltage is use by the ECM as a unit measure for
metered air mass.
REMOVAL
(1) Disconnect the negative battery cable.
(2) Detach the air hose at the Manifold Air Flow
(MAF) sensor
(3) Unplug the MAF wiring harness connector.
(4) Remove the screws retaining the MAF sensor
to the air cleaner housing, and remove MAF sensor.
INSTALLATION
(1) Position the MAF sensor to air cleaner housing
and install the retaining screws (Fig. 21).
(2) Connect the air intake hose to the MAF sensor
and tighten clamp.
(3) connect the MAF wiring harness connector.
(4) Connect negative battery cable.
Fig. 21 MANIFOLD AIR FLOW SENSOR
1 - WIRING HARNESS
2 - AIR INTAKE HOSE
3 - CLAMP
4 - MAF SENSOR
5 - AIR CLEANER HOUSING
VAFUEL INJECTION 14 - 31
MANIFOLD AIR FLOW (MAF) SENSOR (Continued)

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has three primary causes.
(1) Internal clutch slippage, usually caused by low
line pressure, inadequate clutch apply pressure, or
clutch seal failure.
(2) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
(3) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failuredue to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should be replaced whenever
a failure generates sludge and debris. This is neces-
sary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
STANDARD PROCEDURE - CHECK OIL LEVEL
(1) Verify that the vehicle is parked on a level sur-
face.
(2) Remove locking pin (1) (Fig. 136). Remove the
plate of the locking pin with a suitable tool and press
out the pin remaining in the cap downwards.
(3) Remove cap (2).
WARNING: Risk of accident from vehicle starting off
by itself when engine running. Risk of injury from
contusions and burns if you insert your hands into
the engine when it is started or when it is running.
Secure vehicle to prevent it from moving off by
itself. Wear properly fastened and close-fitting work
clothes. Do not touch hot or rotating parts.
Fig. 136 Remove Dipstick Tube Cap Lock
1 - LOCKING PIN
2 - TUBE CAP
3 - DIPSTICK TUBE
21 - 102 AUTOMATIC TRANSMISSION - NAG1VA
FLUID AND FILTER (Continued)

WHEELS
DESCRIPTION
Original equipment wheels are designed for the
specified Maximum Vehicle Capacity.
All models use steel or aluminum wheels.
Aluminum wheels require special balance weights
and alignment equipment.
(1) On vehicles equipped with dual rear wheels,
The slots in the wheel must be aligned to provide
access to the valve stem.
OPERATION
The wheel (Fig. 19) has raised sections between
the rim flanges and the rim well. Initial inflation of
the tire forces the bead over these raised sections. In
case of tire failure, the raised sections hold the tire
in position on the wheel until the vehicle can be
brought to a safe stop.
DIAGNOSIS AND TESTING
WHEEL INSPECTION
Inspect wheels for:
²Excessive run out
²Dents or cracks
²Damaged wheel lug nut holes
²Air Leaks from any area or surface of the rim
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged an original equipment
replacement wheel should be used. When obtainingreplacement wheels, they should be equivalent in
load carrying capacity. The diameter, width, offset,
pilot hole and bolt circle of the wheel should be the
same as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT REPLACE-
MENT WHEELS MAY ADVERSELY AFFECT THE
SAFETY AND HANDLING OF THE VEHICLE. USED
WHEELS ARE NOT RECOMMENDED. THE SERVICE
HISTORY OF THE WHEEL MAY HAVE INCLUDED
SEVERE TREATMENT OR VERY HIGH MILEAGE. THE
RIM COULD FAIL WITHOUT WARNING.
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL
REPLACEMENT
The wheel stud/lugs are designed for specific appli-
cations. They must be replaced with equivalent parts.
Do not use replacement parts of lesser quality or a
substitute design.
Before installing the wheel, be sure to remove any
build up of corrosion on the wheel mounting surfaces.
Ensure wheels are installed with good metal-to-metal
contact. Improper installation could cause loosening
of wheel nuts. This could affect the safety and han-
dling of your vehicle.
To install the wheel, first position it properly on
the mounting surface. All wheel nuts should then be
tightened just snug. Gradually tighten them in
sequence to the proper torque specification.Never
use oil or grease on studs.
Wheels must be replaced if they have:
²Excessive runout
²Bent or dented
²Leak air through welds
²Have damaged bolt holes
Wheel repairs employing hammering, heating, or
welding are not allowed.
Original equipment wheels are available through
your dealer. Replacement wheels from any other
source should be equivalent in:
²Load carrying capacity
²Diameter
²Width
²Offset
²Mounting configuration
Failure to use equivalent replacement wheels may
affect the safety and handling of your vehicle.
Replacement withusedwheels is not recommended.
Their service history may have included severe treat-
ment.
Fig. 19 Safety Rim
1 - FLANGE
2 - RIDGE
3 - WELL
VATIRES/WHEELS 22 - 11

PANEL SECTIONING
If it is required to section a large panel for a plas-
tic repair, it will be necessary to reinforce the panel
(Fig. 1). To bond two plastic panels together, a rein-
forcement must overlap both panels. The panels
must be ªV'dº at a 20 degree angle. The area to be
reinforced should be washed, then sanded. Be sure to
wipe off any excess soap and water when finished.
Lightly sand or abrade the plastic with an abrasive
pad or sandpaper. Blow off any dust with compressed
air or wipe with a clean dry rag.
When bonding plastic panels, Follow repair mate-
rial manufacturers recommendations. Be sure that
enough adhesive has been applied to allow squeeze
out and to fill the full bond line. Once the pieces
have been brought together, do not move them until
the adhesive is cured. The assembly can be held
together with clamps, rivets, etc. A faster cure can be
obtained by heating with a heat lamp or heat gun.
After the parts have been bonded and have had time
to cure, rough sand the seam and apply the final
adhesive filler to the area being repaired. Smooth the
filler with a spreader, wooden tongue depressor, or
squeegee. For fine texturing, a small amount of
water can be applied to the filler surface while
smoothing. The cured filler can be sanded as neces-
sary and, as a final step, cleanup can be done with
soapy water. Wipe the surface clean with a dry cloth
allowing time for the panel to dry before moving on
with the repair.
PANEL REINFORCEMENT
Structural repair procedures for rigid panels with
large cracks and holes will require a reinforcement
backing. Reinforcements can be made with severalapplications of glass cloth saturated with structural
adhesive. Semi-rigid or flexible repair materials
should be used for semi-rigid or flexible backing rein-
forcement (Fig. 2) and (Fig. 3). Open meshed fiber-
glass dry wall tape can be used to form a
reinforcement. The dry wall tape allows the resin to
penetrate through and make a good bond between
the panel and the adhesive. Structurally, the more
dry wall tape used, the stronger the repair.
Another kind of repair that can be done to repair
large cracks and holes is to use a scrap piece of sim-
ilar plastic and bond with structural adhesive. The
reinforcement should cover the entire break and
should have a generous amount of overlap on either
side of the cracked or broken area.
When repairing plastic, the damaged area is first
ªV'dº out, or beveled. Large bonding areas are desir-
able when repairing plastic because small repairs are
less likely to hold permanently. Beveling the area
around a crack at a 20 degree angle will increase the
bonding surface for a repair (Fig. 4). It is recom-
mended that sharp edges be avoided because the
joint may show through after the panel is refinished.
²Panel repair for both flexible and rigid panels
are basically the same. The primary difference
between flexible panel repair and rigid panel repair
is in the adhesive materials used (Fig. 5).
Fig. 1 PANEL SECTIONING
1 - EXISTING PANEL
2 - NEW PANEL
3 - PANEL ADHESIVE
4 - BONDING STRIP
Fig. 2 SOFTENED EDGES
1 - SOFTENED EDGES
2 - PANEL ADHESIVE
3 - BONDING STRIP
Fig. 3 PANEL REINFORCEMENT
1 - PANEL ADHESIVE
2 - REINFORCEMENT
23 - 6 BODYVA
BODY (Continued)

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)