2006 MERCEDES-BENZ SPRINTER sensor

(6) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
AIR OUTLET TEMPERATURE
SENSOR
DESCRIPTION
The air outlet temperature sensor is a two-wire
temperature sensing element that detects the tem-
perature of the air coming out of the heater housing
unit (Fig. 11). The sensor is attached to heater hous-
ing unit directly behind the ATC heater-A/C control
panel. The thermistor will change resistance as the
temperature changes.
OPERATION
The air outlet temperature sensor monitors the
temperature of the air coming out of the heater hous-
ing unit. The sensor will change its internal resis-
tance in response to the temperatures it monitors.
The ATC control module is connected to the sensor
through a sensor ground circuit and a sensor signal
circuit. As the air temperature increases, the resis-
tance of the sensor decreases and the voltage moni-
tored by the module decreases. The operating range
of the air outlet temperature sensor is 0É C (32É F)
and 95É C (203É F). The module uses this monitored
voltage reading to an indication of the outlet air tem-
perature. The ATC control module makes adjust-
ments to maintain the requested interior
temperature by cycling both the A/C compressor and
solenoid heater valve on and off.The air outlet temperature sensor is diagnosed by
performing the ATC Function Test using the DRBIIIt
scan tool. Refer to Body Diagnostic Procedures.
The air outlet temperature sensor cannot be
adjusted or repaired, and if faulty or damaged, it
must be replaced.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the heater-A/C control from the instru-
ment panel (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS/A/C HEATER CONTROL -
REMOVAL).
(3) Disconnect the wire harness connector from the
air outlet temperature sensor (Fig. 12).
(4) Remove the air outlet temperature sensor from
the heater housing.
INSTALLATION
(1) Install the air outlet temperature sensor onto
the heater housing.
(2) Connect the wire harness connector to the air
outlet temperature sensor.
(3) Install the heater-A/C control into the instru-
ment panel (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS/A/C HEATER CONTROL -
INSTALLATION).
(4) Reconnect the battery negative cable.
Fig. 11 Air Outlet Temperature Sensor
1 - AIR OUTLET TEMPERATURE SENSOR
2 - NTC THERMISTOR
3 - WIRE CONNECTORFig. 12 Air Outlet Temperature Sensor
1 - HEATER HOUSING
2 - AIR OUTLET TEMPERATURE SENSOR
24 - 16 CONTROLS-FRONTVA

AMBIENT TEMPERATURE SEN-
SOR
DESCRIPTION
The ambient air temperature sensor is a variable
resistor that monitors the air temperature outside of
the vehicle. The ambient air temperature sensor is
connected to the instrument cluster through a two-
wire harness lead and connector of the vehicle elec-
trical system (Fig. 13). The instrument cluster sends
out a message on the CAN bus to the ATC control
module which uses the sensor data to maintain opti-
mum cabin temperature levels.
The ambient air temperature sensor is mounted to
the front licence plate bracket by three integral
retaining tabs.
OPERATION
The ambient temperature sensor is a variable
resistor that operates on a five-volt reference signal
sent to it by the instrument cluster. The resistance in
the sensor changes as temperature changes. Based
upon the resistance in the sensor, the instrument
cluster sends the ATC control module a specific volt-
age on the temperature sensor signal circuit, which
is programmed to correspond to a specific tempera-
ture.
The ambient temperature sensor is diagnosed
using the DRBIIItscan tool. Refer to Body Diagnos-
tic Procedures.
The ambient temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, it
must be replaced.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the front license plate bracket (Refer
to 23 - BODY/EXTERIOR/LICENSE PLATE
BRACKET - REMOVAL).
(3) Disconnect the wire harness connector from the
ambient temperature sensor (Fig. 14).
(4) Disengage the sensor retaining tabs and
remove the ambient temperature sensor from the
front license plate bracket.
INSTALLATION
(1) Install the ambient temperature sensor onto
the front license plate bracket. Make sure the retain-
ing tabs are fully engaged.
(2) Connect the wire harness connector to the
ambient temperature sensor.
(3) Install the front license plate bracket (Refer to
23 - BODY/EXTERIOR/LICENSE PLATE BRACKET
- INSTALLATION).
(4) Reconnect the battery negative cable.
BLOWER MOTOR RESISTOR
DESCRIPTION
This temperature control system uses a blower
motor resistor (Fig. 15). The blower motor resistor is
mounted to the top of ventilation housing located in
the engine compartment. The blower motor resistor
consists of a molded plastic mounting plate with an
integral retaining tab and wire connector receptacle.
Concealed behind the mounting plate are coiled resis-
tor wires contained within a ceramic heat sink.
Fig. 13 Ambient Air Temperature Sensor
1 - AMBIENT TEMPERATURE SENSOR
2 - WIRE HARNESS CONNECTOR
3 - RETAINING TABS (3)
Fig. 14 Ambient Temperature Sensor
1 - AMBIENT TEMPERATURE SENSOR
2 - FRONT LICENSE PLATE BRACKET
VACONTROLS-FRONT 24 - 17

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

The external location of the sensor allows the sensor
to be removed or installed without disturbing the
refrigerant in the A/C system.
The evaporator temperature sensor is diagnosed by
performing the ATC Function Test using a DRBIIIt
scan tool. Refer to Body Diagnostic Procedures.
The evaporator temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, it
must be replaced.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the radio (Refer to 8 - ELECTRICAL/
AUDIO/RADIO - REMOVAL).
(3) Remove glove compartment.
(4) Remove cover from instrument cluster (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - REMOVAL).
(5) Remove the instrument cluster (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER -
REMOVAL).
(6) Remove passenger side airbag.
(7) Remove cover above air nozzle on passenger
side.
(8) Remove speaker.
(9) Remove center section of instrument panel.
(10) Remove A/C-heater control from the instru-
ment panel (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS/A/C HEATER CONTROL -
REMOVAL).
(11) Remove instrument panel top section.
(12) Remove electrical connections.
(13) Remove air bezels from instrument panel.
(14) Disconnect the wire harness connector from
evaporator temperature sensor (Fig. 19).
(15) Remove evaporator temperature sensor from
HVAC housing.
INSTALLATION
(1) Install the probe of the evaporator temperature
sensor between the fins of the A/C evaporator.
NOTE: The probe must not go into the same hole
(in the A/C evaporator ) that the probe was removed
from.
(2) Install the wire harness connector to the evap-
orator temperature sensor.
(3) Install the air bezels to the instrument panel.
(4) Install the electrical connections.
(5) Install the instrument panel top section (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - INSTALLATION).
(6) Install the A/C-heater control (Refer to 24 -
HEATING & AIR CONDITIONING/CONTROLS/A/C
HEATER CONTROL - INSTALLATION).
(7) Install the center section of the instrument
panel.
(8) Install the speaker (Refer to 8 - ELECTRICAL/
AUDIO/SPEAKER - INSTALLATION).
(9) Install the cover above the air nozzle on the
passenger side.
(10) Install the passenger side airbag.
(11) Install the instrument cluster (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - INSTAL-
LATION).
(12) Install the cover to the instrument cluster.
(13) Install glove compartment.
(14) Install the radio (Refer to 8 - ELECTRICAL/
AUDIO/RADIO - INSTALLATION).
(15) Reconnect the negative battery cable.
Fig. 19 Evaporator Temperature Sensor
1 - WIRE HARNESS CONNECTOR
2 - EVAPORATOR TEMPERATURE SENSOR
24 - 20 CONTROLS-FRONTVA

IN - CAR TEMPERATURE SEN-
SOR
DESCRIPTION
The in-car temperature sensor measures the actual
air temperature within the passenger compartment.
The in-car temperature sensor is located inside of the
A/C-heater control behind a vented panel (Fig. 20)
and is not a separate serviceable component. The
A/C-heater control must be replaced if there is a fault
relating to the in-car temperature sensor.
OPERATION
Air from the passenger compartment flows over the
thermistor of the in-car temperature sensor. The
thermistor changes resistance with air temperature.
The ATC A/C-heater control measures this resistance
and calculates the temperature of the air. The A/C-
heater control then makes adjustments to maintain
the selected passenger compartment temperature.
The in-car temperature sensor 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
IN - CAR TEMPERATURE SENSOR
The in-car temperature sensor is diagnosed by per-
forming the ATC Function Test using the DRBIIIt
scan tool. Refer to Body Diagnostic Procedures. For
circuit descriptions and diagrams, refer to the appro-
priate wiring information.
MODE DOOR CABLES
REMOVAL
The air distribution control cables (mode door
cables) can be removed and installed without having
to remove the instrument panel from the vehicle.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(3) Remove the A/C-heater control (Refer to 24 -
HEATING & AIR CONDITIONING/CONTROLS/A/C
HEATER CONTROL - REMOVAL).
(4) Mark and disconnect the control cables from
the A/C-heater control.
(5) Mark and disconnect the control cables from
the HVAC housing retainers (Fig. 21).
(6) Disconnect the control cables from the mode
door levers and remove the cables from the vehicle.
INSTALLATION
(1) Connect the two control cables to the mode
door levers (Fig. 22).
(2) Connect the two control cables to the A/C-
heater control.
NOTE: Install the control cable of bottom adjust-
ment lever to the front adjustment wheel of the A/C-
heater control.
(3) Hold the A/C-heater control in its installation
position.
Fig. 20 In-Car Temperature Sensor
1 - A/C-HEATER CONTROL
2 - IN-CAR TEMPERATURE SENSOR
Fig. 21 Air Distribution Control Cables
1 - AIR DISTRIBUTION CONTROL CABLES
2 - ADJUSTMENT LEVERS
3 - HVAC HOUSING
VACONTROLS-FRONT 24 - 21

CONTROLS - REAR
TABLE OF CONTENTS
page page
A/C CLUTCH RELAY
DESCRIPTION.........................24
OPERATION...........................25
REMOVAL.............................25
INSTALLATION.........................26
A/C CONDENSER FAN RELAY
DESCRIPTION.........................26
OPERATION...........................26
REMOVAL.............................27
INSTALLATION.........................28
A/C CONTROL MODULE
DESCRIPTION.........................28
OPERATION...........................28
REMOVAL.............................29
INSTALLATION.........................30
A/C HIGH PRESSURE SWITCH
DESCRIPTION.........................30
OPERATION...........................30
REMOVAL.............................31
INSTALLATION.........................31
A/C LOW PRESSURE SWITCH
DESCRIPTION.........................32
OPERATION...........................32
REMOVAL.............................32
INSTALLATION.........................33
BLOWER MOTOR RELAY
DESCRIPTION.........................33
OPERATION...........................33
REMOVAL.............................34
INSTALLATION.........................35
BLOWER MOTOR SWITCH
DESCRIPTION.........................35
OPERATION...........................35
DIAGNOSIS AND TESTING
REAR BLOWER MOTOR SWITCH.........36REMOVAL.............................36
INSTALLATION.........................37
EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................37
OPERATION...........................37
REMOVAL.............................37
INSTALLATION.........................38
TEMPERATURE CONTROL
DESCRIPTION.........................38
OPERATION...........................38
DIAGNOSIS AND TESTING
REAR A/C TEMPERATURE CONTROL.....39
REMOVAL.............................39
INSTALLATION.........................40
TEMPERATURE SENSOR
DESCRIPTION.........................40
OPERATION...........................40
DIAGNOSIS AND TESTING
REAR TEMPERATURE SENSOR..........40
REMOVAL.............................40
INSTALLATION.........................41
SUPPRESSOR FILTER - REAR BLOWER
MOTOR
DESCRIPTION.........................41
OPERATION...........................41
REMOVAL.............................42
INSTALLATION.........................43
SUPPRESSOR FILTER - REAR CONDENSER
FA N
DESCRIPTION.........................43
OPERATION...........................44
REMOVAL.............................44
INSTALLATION.........................44
A / C CLUTCH RELAY
DESCRIPTION
The rear A/C clutch relay for the rear A/C system
is an International Standards Organization (ISO)-
type relay (Fig. 1). Relays conforming to the ISO
specifications have common physical dimensions, cur-
rent capacities, terminal functions and patterns. The
rear A/C clutch relay is an electromechanical device
that uses a low current input controlled by the rear
A/C control module to control the high current output
to the A/C clutch field coil for the rear A/C system.The rear A/C clutch relay is located in the relay
block in the rear A/C evaporator housing.
24 - 24 CONTROLS - REARVA

INSTALLATION
(1) Position the rear A/C condenser fan relay into
the proper receptacle of the relay block located in the
rear A/C evaporator housing.
(2) Align the A/C condenser fan relay terminals
with the terminal cavities in the relay block recepta-
cle and push down firmly on the relay until the ter-
minals 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 CONTROL MODULE
DESCRIPTION
The rear A/C control module (Fig. 5) is connected
to the rear A/C blower motor switch, rear evaporative
temperature sensor, rear A/C temperature control
and the temperature sensor.
The rear A/C control module is located in the upper
left side of the rear A/C evaporator housing.
OPERATION
The rear A/C control module is supplied fused bat-
tery power through the rear blower switch. The con-
trol module receives input signals from the rear A/C
blower motor switch, rear A/C temperature control,
rear temperature sensor and the rear evaporator
temperature sensor when the front A/C switch is
turned on. The rear A/C control module uses the
Fig. 4 Rear A/C Condenser Fan 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. 5 Rear A/C Control Module
1 - REAR A/C CONTROL MODULE
2 - MOUNTING TABS
3 - WIRE HARNESS CONNECTOR
24 - 28 CONTROLS - REARVA

motor, while relay 2 when activated, sends power
directly to the blower motor.
The rear blower motor switch cannot be repaired
and, if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING
REAR BLOWER MOTOR SWITCH
Before testing the rear blower motor switch, verify
that the front A/C system is functional by performing
the ATC Fuction Test using the DRBIIItscan tool.
Use a volt/ohmmeter to test the rear blower motor
switch. For circuit descriptions and diagrams, refer
to the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, details of wire har-
ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
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.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the
rear blower motor switch.
(3) Check for continuity between terminal 10 and
terminals 1, 7 and 4 of the blower motor switch. In
all instances, there should be continuity.
NOTE: To check the switch's internal circuits, con-
nect the negative lead of the ohmmeter to terminal
10 and the positive ohmmeter lead to terminals 1, 7
and 4. To check the switch's integral light emitting
diodes, reverse the ohmmeter leads.
(4) Check for continuity between the rear blower
motor switch terminals 3 and 7 as you move the
blower motor switch to each of the two speed posi-
tions, and the Off position. There should be continu-
ity in only one blower motor switch speed position.
(5) Check for continuity between the rear blower
motor switch terminals 4 and 8 as you move the
blower motor switch to each of the two speed posi-
tions, and the Off position. There should be continu-ity in only the other blower motor switch speed
position.
(6) If OK, test and repair the rear blower motor
switch wire harness circuits. If not OK, replace the
faulty rear blower motor switch.
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.
NOTE: The rear A/C blower motor switch is used on
vehicles with the optional rear A/C system.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the accessory switch panel from the
instrument panel (Refer to 23 - BODY/INSTRU-
MENT PANEL/ACCESSORY SWITCH BEZEL -
REMOVAL).
(3) Disconnect the wire harness connector from the
rear A/C blower motor switch (Fig. 14).
(4) Disengage the retaining tabs and remove the
rear A/C blower motor switch from the accessory
switch panel.
24 - 36 CONTROLS - REARVA