Mercedes-Benz 2005 Sprinter Service Manual page 1144

24 - 16 CONTROLS - FRONT
AMBIENT TEMPERATURE SENSOR (Continued)
(4) Disconnect the wire harness connector from the
sensor and remove the sensor from the vehicle.
Fig. 11 Ambient Temperature Sensor
1 - AMBIENT TEMPERATURE SENSOR
2 - FRONT FASCIA
INSTALLATION
(1) Connect the wire harness connector to the
ambient temperature sensor.
(2) Install the sensor onto the front fascia through
the access hole in the fascia.
(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
BLOCK
DESCRIPTION
This temperature control system uses a blower
motor resistor. The blower motor resistor is mounted
to the top of ventilation housing located in the engine
compartment. The blower motor resistor can be
accessed for service without removing any other com-
ponents.
OPERATION
The blower motor resistor block has multiple resis-
tor wires. Each resistor wire changes the resistance
in the blower motor current path to change the
blower motor speed. The blower motor switch directs
the current through the correct resistor wire to
obtain the selected speed.
With the blower motor switch in the lowest speed
position, voltage for the motor is applied through all
of the resistor wires. Each higher speed selected with
the blower motor switch applies the blower motor
current path through fewer of the resistor wires,
increasing the blower motor speed. When the blower
motor switch is in the highest speed position, the
blower motor resistor is bypassed and the blower
motor circuit receives a direct path to battery volt-
age.
The blower motor resistor block cannot be repaired
and, if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR BLOCK
For circuit descriptions and diagrams, refer to the
appropriate wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the
blower motor resistor block.
(3) Check for continuity between each of the
blower motor switch input terminals of the resistor
and the resistor output terminal. In each case there
should be continuity. If OK, repair the wire harness
circuits between the blower motor switch and the
blower motor resistor or blower motor as required. If
not OK, replace the faulty blower motor resistor.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Depress resistor block locking tab and remove
resistor block from the ventilation housing by sliding
the resistor block inboard (Fig. 12).
(3) Depress two locking tabs and unplug the wire
harness connector from the blower motor resistor
block.
(4) Remove the blower motor resistor from the
engine compartment.
VA