2006 MERCEDES-BENZ SPRINTER heater

INSTALLATION
(1) Position the MAF sensor to air cleaner housing
and install the retaining screws (Fig. 24).
(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.
O2 SENSOR
DESCRIPTION
The wide band oxygen sensor measures the oxygen
content in the exhaust gas to monitor EGR. The sen-
sor is mounted in the exhaust pipe at a 30 degree
angle to prevent the collection of moisture between
the sensor housing and element. The sensor is
located close to the turbocharger for a quicker
response time.
The oxygen sensor has five wires (heater power
and ground, reference voltage, and 2 wires for a
pump cell). The oxygen sensor connects to a six wire
harness connector. A non serviceable trimming resis-
tor is built into the sensor connector. The resistance
is dependent on the over all length and type of sen-
sor.
OPERATION
The O2 sensor is a planar zirconium dioxide (ZrO2)
dual cell limiting current probe with a integralheater. The term wide ban, refers to the ability of the
O2 sensor to generate a clear signal over a wide air-
fuel ratio measuring range. As a dual sensor, it incor-
porates a second O2 chamber (oxygen pump cell),
which requires a separate voltage supply.
The sensor element combines a sensor cell (8) and
an oxygen pump cell (9). Both cells are made of zir-
conium-dioxide (ZrO2) and are coated with porous
platinum electrodes. The sensor cell operates just
like a typical O2 sensor. The oxygen pump cell trans-
port oxygen ions when voltage is applied.
A gas sample chamber (5) is sandwiched between
the oxygen pump cell and the sensor cell. A pump
electrode and sensor cell electrode are located in the
sample chamber. A sample passage (10) connects the
sample chamber to the surrounding exhaust gas. A
sensor cell electrode is located in the reference air
channel (6), which connects to the outside air (Fig.
25).
Fig. 24 MANIFOLD AIR FLOW SENSOR
1 - WIRING HARNESS
2 - AIR INTAKE HOSE
3 - CLAMP
4 - MAF SENSOR
5 - AIR CLEANER HOUSING
VAFUEL INJECTION 14 - 45

At high temperatures, certain ceramic materials,
such as zirconium-dioxide (ZrO2) become oxygen ion
conductors. In a typical O2 sensor, the ZrO2 is used
as a solid electrolyte, which conducts oxygen ions.
The solid electrolyte is sandwiched between two plat-
inum electrodes. The sensor generates a small volt-
age when oxygen moves from the high concentration
side to the low concentration side.
The same hold true if the process is reversed. If
voltage is applied to the platinum electrodes, oxygen
can be pumped from one side of the solid electrolyte
to the other (from cathode to anode), becoming an
oxygen pump. The amount of current flow is directly
proportional to the amount of oxygen pumped by the
sensor. When the oxygen level on the supply side
reaches zero, the current stops.
The ECM activates the integral heater element to
raise the temperature of the sensor to 700C (192ÉF)
for the ZrO2 to become conductive. The heater ele-
ment is designed to reach this temperature within 8seconds and maintaining it at this level. In cold tem-
peratures, this can be delayed up to 5 minutes to
prevent damaging the ceramic coating of the sensor
from water condensation. Once the sensor is heated,
the exhaust gas components diffuse through the gas
sample chamber. Upon reaching the electrodes on the
oxygen pump and concentration cells they reach state
of thermodynamic balance (Fig. 26).
Fig. 25 O2 CONSTRUCTION
1 - EXHAUST PIPE 6 - REFERENCE AIR CHANNEL
2 - EXHAUST GAS FLOW 7 - HEATER ELEMENT
3 - O2 SENSOR CONNECTOR 8 - SENSOR CELL
4 - TRIMMING RESISTOR 9 - OXYGEN PUMP CELL
5 - GAS SAMPLE CHAMBER 10 - SAMPLE PASSAGE
14 - 46 FUEL INJECTIONVA

aligned and sealed. If component alignment or seal-
ing is necessary, refer to the appropriate section of
this group for proper procedures.
WATER LEAK TESTS
WARNING: DO NOT USE ELECTRIC SHOP LIGHTS
OR TOOLS IN WATER TEST AREA. PERSONAL
INJURY CAN RESULT.
When the conditions causing a water leak have
been determined, simulate the conditions as closely
as possible.
²If a leak occurs with the vehicle parked in a
steady light rain, flood the leak area with an open-
ended garden hose.
²If a leak occurs while driving at highway speeds
in a steady rain, test the leak area with a reasonable
velocity stream or fan spray of water. Direct the
spray in a direction comparable to actual conditions.
²If a leak occurs when the vehicle is parked on an
incline, hoist the end or side of the vehicle to simu-
late this condition. This method can be used when
the leak occurs when the vehicle accelerates, stops or
turns. If the leak occurs on acceleration, hoist the
front of the vehicle. If the leak occurs when braking,
hoist the back of the vehicle. If the leak occurs on left
turns, hoist the left side of the vehicle. If the leak
occurs on right turns, hoist the right side of the vehi-
cle. For hoisting recommendations (Refer to LUBRI-
CATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE).
WATER LEAK DETECTION
To detect a water leak point-of-entry, do a water
test and watch for water tracks or droplets forming
on the inside of the vehicle. If necessary, remove inte-
rior trim covers or panels to gain visual access to the
leak area. If the hose cannot be positioned without
being held, have someone help do the water test.
Some water leaks must be tested for a considerable
length of time to become apparent. When a leak
appears, find the highest point of the water track or
drop. The highest point usually will show the point of
entry. After leak point has been found, repair the
leak and water test to verify that the leak has
stopped.
Locating the entry point of water that is leaking
into a cavity between panels can be difficult. The
trapped water may splash or run from the cavity,
often at a distance from the entry point. Most water
leaks of this type become apparent after accelerating,
stopping, turning, or when on an incline.
MIRROR INSPECTION METHOD
When a leak point area is visually obstructed, use
a suitable mirror to gain visual access. A mirror canalso be used to deflect light to a limited-access area
to assist in locating a leak point.
BRIGHT LIGHT LEAK TEST METHOD
Some water leaks in the luggage compartment can
be detected without water testing. Position the vehi-
cle in a brightly lit area. From inside the darkened
luggage compartment inspect around seals and body
seams. If necessary, have a helper direct a drop light
over the suspected leak areas around the luggage
compartment. If light is visible through a normally
sealed location, water could enter through the open-
ing.
PRESSURIZED LEAK TEST METHOD
When a water leak into the passenger compart-
ment cannot be detected by water testing, pressurize
the passenger compartment and soap test exterior of
the vehicle. To pressurize the passenger compart-
ment, close all doors and windows, start engine, and
set heater control to high blower in HEAT position. If
engine can not be started, connect a charger to the
battery to ensure adequate voltage to the blower.
With interior pressurized, apply dish detergent solu-
tion to suspected leak area on the exterior of the
vehicle. Apply detergent solution with spray device or
soft bristle brush. If soap bubbles occur at a body
seam, joint, seal or gasket, the leak entry point could
be at that location.
DIAGNOSIS AND TESTING - WIND NOISE
Wind noise is the result of most air leaks. Air leaks
can be caused by poor sealing, improper body compo-
nent alignment, body seam porosity, or missing plugs
in the engine compartment or door hinge pillar areas.
All body sealing points should be airtight in normal
driving conditions. Moving sealing surfaces will not
always seal airtight under all conditions. At times,
side glass or door seals will allow wind noise to be
noticed in the passenger compartment during high
cross winds. Over compensating on door or glass
adjustments to stop wind noise that occurs under
severe conditions can cause premature seal wear and
excessive closing or latching effort. After a repair pro-
cedure has been performed, test vehicle to verify
noise has stopped before returning vehicle to use.
VISUAL INSPECTION BEFORE TESTS
Verify that floor and body plugs are in place and
body components are aligned and sealed. If compo-
nent alignment or sealing is necessary, refer to the
appropriate section of this group for proper proce-
dures.
ROAD TESTING WIND NOISE
(1) Drive the vehicle to verify the general location
of the wind noise.
23 - 2 BODYVA

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, OR INSTRU-
MENT PANEL COMPONENT DIAGNOSIS OR SER-
VICE. DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE, THEN WAIT TWO
MINUTES FOR THE AIRBAG SYSTEM CAPACITOR
TO DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
²WHEN REMOVING A DEPLOYED AIRBAG, RUB-
BER GLOVES, EYE PROTECTION, AND A LONG-
SLEEVED SHIRT SHOULD BE WORN. THERE MAY
BE DEPOSITS ON THE AIRBAG UNIT AND OTHER
INTERIOR SURFACES. IN LARGE DOSES, THESE
DEPOSITS MAY CAUSE IRRITATION TO THE SKIN
AND EYES.
²USE EXTREME CARE TO PREVENT ANY FOR-
EIGN MATERIAL FROM ENTERING THE PASSEN-
GER AIRBAG, OR BECOMING ENTRAPPED
BETWEEN THE PASSENGER AIRBAG CUSHION
AND THE PASSENGER AIRBAG DOOR. FAILURE TO
OBSERVE THIS WARNING COULD RESULT IN
OCCUPANT INJURIES UPON AIRBAG DEPLOY-
MENT.
²THE PASSENGER AIRBAG DOOR MUST
NEVER BE PAINTED. REPLACEMENT PASSENGER
AIRBAGS ARE SERVICED WITH DOORS IN THE
ORIGINAL COLORS. PAINT MAY CHANGE THE WAY
IN WHICH THE MATERIAL OF THE AIRBAG DOOR
RESPONDS TO AN AIRBAG DEPLOYMENT. FAIL-
URE TO OBSERVE THIS WARNING COULD RESULT
IN OCCUPANT INJURIES UPON AIRBAG DEPLOY-
MENT.
(1) Install the instrument panel.
NOTE: The guides on the bottom of the instrument
panel must engage in the cutouts on the left and
right next to the heater housing. (Fig. 21) (Fig. 22)(2) Route wire harness through the panel.
(3) Install and tighten 12 instrument panel screws.
(Fig. 20)
CAUTION: The position of the steering gear must
not be altered.
(4) Raise steering column into position and install
the bolts. (Fig. 19)
(5) Tighten steering column bolts to 25 N´m (18 ft.
lbs.).
(6) Install ignition transponder onto column lock.
(Fig. 18)
NOTE: The dome on the transponder must engage
into the groove on the ignition switch.
(7) Install brake pedal spring. (Fig. 17)
(8) Install vent hose. (Fig. 16)
Fig. 21 ALIGNMENT CUTOUT - 1
1 - CUTOUT
2 - HEATER HOUSING
Fig. 22 ALIGNMENT CUTOUT - 2
1 - CUTOUT
2 - HEATER HOUSING
VAINSTRUMENT PANEL 23 - 63

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING
A/C PERFORMANCE....................3
HEATER PERFORMANCE TEST...........5
ATC FUNCTION TEST...................6
SPECIFICATIONS
HEATING-A/C SYSTEM..................6CONTROLS-FRONT........................8
CONTROLS - REAR......................24
DISTRIBUTION - FRONT...................45
DISTRIBUTION - REAR....................52
PLUMBING.............................60
CABIN HEATER.........................104
HEATING & AIR CONDITION-
ING
DESCRIPTION
An automatic temperature control (ATC) single
zone type heating-A/C system is standard equipment
on this model.
To maintain the performance level of the heating,
ventilation and air conditioning (HVAC) 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 A/C condenser
will reduce the performance of the A/C and engine
cooling systems.
The engine cooling system includes the radiator,
thermostat, radiator hoses and the engine coolant
pump. Refer to 7 - Cooling for more information
before opening or attempting any service to the
engine cooling system.
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 block
²Recirculation door and actuator
All vehicles are also equipped with a common
heater housing (Fig. 2) mounted under the instru-
ment panel which includes:
²Heater core
²Evaporator core
²Evaporator temperature sensor
²Expansion valve
²Air outlet temperature sensor
²Mode doors
Fig. 1 Ventilation Housing
1 - NUT (5)
2 - WASHER (5)
3 - VENTILATION HOUSING
4 - HOUSING COVER
VAHEATING & AIR CONDITIONING 24 - 1

Some vehicles are equipped with an additional
Denso 10S17 A/C compressor mounted to the engine
which is used for the optional rear A/C system and
various add-on A/C systems (Fig. 3).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. 4).
OPERATION
Outside air enters the vehicle through the hood
opening at the base of the windshield, and passes
through 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.
Fig. 2 Heater Housing
1 - SCREW (12)
2 - UPPER HOUSING
3 - A/C EVAPORATOR
4 - EVAPORATOR O-RING SEAL (2)
5 - EVAPORATOR GASKET
6 - VENTILATION HOUSING GASKET
7 - LOWER 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 Denso 10S17 A/C Compressor
Fig. 4 Heater Booster
24 - 2 HEATING & AIR CONDITIONINGVA

When the outside air contains smoke, odors, 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
vacuum actuator. When the Recirculation Mode is
selected, the recirculation door is closed to prevent
outside air from entering the passenger compart-
ment.
To maintain minimum evaporator temperature and
prevent evaporator freezing, an evaporator tempera-
ture sensor is used.
The A/C system is designed for the use of non-CFC,
R-134a refrigerant only and uses an expansion valve
to meter refrigerant flow to the evaporator.
DIAGNOSIS AND TESTING
A / C PERFORMANCE
The A/C system is designed to provide the passen-
ger compartment with low temperature and low
humidity air. The A/C evaporator, located in the
HVAC housing is cooled to temperatures near the
freezing point. As warm damp air passes over the
fins of the A/C evaporator, the air transfers its heat
to the refrigerant in the evaporator coils and the
moisture in the air condenses on the evaporator fins.
During periods of high heat and humidity, an A/C
system will be more effective in the Recirculation
mode (max-A/C). With the system in the Recircula-
tion mode, only air from the passenger compartment
passes through the A/C evaporator. As the passenger
compartment air dehumidifies, the A/C system per-
formance levels rise.
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 A/C system.
When humidity is high, the A/C evaporator has to
perform a double duty. It must lower the air temper-
ature, and it must lower the temperature of the
moisture in the air that condenses on the evaporator
fins. Condensing the moisture in the air transfers
heat energy into the evaporator fins and coils. This
reduces the amount of heat the A/C evaporator can
absorb from the air. High humidity greatly reduces
the ability of the A/C evaporator to lower the temper-
ature of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Wring-
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
A/C system on humid days. A performance test is the
best way to determine whether the system is per-
forming up to design standards. This test also pro-
vides valuable clues as to the possible cause oftrouble with the A/C system. The ambient air tem-
perature in the location where the vehicle will be
tested must be a minimum of 21É C (70É F) for this
test.
A / C PERFORMANCE TEST
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: 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.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Check for diagnostic trouble codes using a
DRBIIItscan tool. If no DTCs are found in the
engine control module (ECM), go to Step 2. If any
DTCs are found, repair as required, then proceed to
Step 2.
(2) Place the vehicle in the shade and operate the
heating-A/C system under the following conditions.
²Engine at idle at operating temperature
²All doors or windows open
²Transaxle in Neutral
²All A/C duct louvers open
²A/C-heater controls set to fresh air (NOT Recir-
culate), full cool, panel mode, high blower and with
A/C compressor engaged.
NOTE: The A/C compressor clutch is de-energized
under any of the following conditions:
²Restricted compressor (thermal fuse in the pul-
ley)
²Low pressure in the system
²Low evaporator temperature
²Hard acceleration (WOT)
²High coolant temperatures
(3) Insert a thermometer in the driver side center
panel air outlet and operate the A/C system until the
thermometer temperature stabilizes.
VAHEATING & AIR CONDITIONING 24 - 3

Condition Possible Causes Correction
The low side pressure is
normal or slightly low, and
the high side pressure is too
low.1. Low refrigerant system
charge.1. See Refrigerant System Leaks in this
group. Test the refrigerant system for leaks.
Repair, evacuate and charge the refrigerant
system, if required.
2. Refrigerant flow through the
A/C evaporator is restricted.2. See A/C Evaporator in this group. Replace
the restricted A/C evaporator, if required.
3. Faulty A/C compressor. 3. See A/C Compressor in this group. Re-
place the A/C compressor, if required.
The low side pressure is
normal or slightly high, and
the high side pressure is too
high.1. A/C condenser air flow re-
stricted.1. Check the A/C condenser for damaged
fins, foreign objects obstructing air flow
through the condenser fins, and missing or
improperly installed air seals. Clean, repair, or
replace components as required.
2. Refrigerant flow through the
receiver/drier is restricted.2. See Receiver/Drier in this group. Replace
the restricted receiver/drier, if required.
3. Inoperative radiator cooling
fan.3. Test the radiator cooling fan and replace, if
required. Refer to Group 7 - Cooling.
4. Refrigerant system over-
charged.4. See Refrigerant System Charge in this
group. Recover the refrigerant from the refrig-
erant system. Charge the refrigerant system
to the proper level, if required.
5. Air in the refrigerant system. 5. See Refrigerant System Leaks in this
group. Test the refrigerant system for leaks.
Repair, evacuate and charge the refrigerant
system, if required.
6. Engine overheating. 6. Test the engine cooling system and repair,
if required. Refer to Group 7 - Cooling.
The low side pressure is too
high, and the high side pres-
sure is too low.1. Accessory drive belt slip-
ping.1. Inspect the accessory drive belt condition
and tension. Repair as required. Refer to
Group 7 - Cooling.
2. Faulty A/C expansion valve. 2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Faulty A/C compressor. 3. See A/C Compressor in this group. Re-
place the A/C compressor, if required.
The low side pressure is too
low, and the high side pres-
sure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid Line, Suction Line and Dis-
charge Line in this group. Inspect the refriger-
ant lines for kinks, tight bends or improper
routing. Correct the routing or replace the re-
frigerant line, if required.
2. Restricted refrigerant flow
through the A/C expansion
valve.2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Restricted refrigerant flow
through the A/C condenser.3. See A/C Condenser in this group. Replace
the restricted A/C condenser, if required.
HEATER PERFORMANCE TEST
Before performing the following tests, perform the
ATC Function Test using the DRBIIItand refer to
Cooling 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
VAHEATING & AIR CONDITIONING 24 - 5