Dodge Viper SRT-10 (ZB). Manual - part 262

blower motor speed. When the blower motor control
is in the highest speed position, the blower motor
resistor is bypassed and the blower motor receives a
direct path to ground.

The blower motor resistor cannot be adjusted or

repaired and, if faulty or damaged, it must be
replaced.

DIAGNOSIS AND TESTING

BLOWER MOTOR RESISTOR

WARNING: On vehicles equipped with airbags, dis-
able the airbag system before attempting any steer-
ing wheel, steering column, or instrument panel
component diagnosis or service. Disconnect and
isolate the negative battery (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 air-
bag system. Failure to take the proper precautions
could result in accidental airbag deployment and
possible personal injury or death.

NOTE: For circuit descriptions and diagrams, refer
to the appropriate wiring information. The wiring

information includes wiring diagrams, proper wire
and connector repair procedures, further details on
wire harness routing and retention, as well as pin-
out and location views for the various wire harness
connectors, splices and grounds.

(1) Disconnect and isolate the negative battery

cable.

(2) Disconnect the wire harness connector from the

blower motor resistor (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/BLOWER

MOTOR

RESISTOR - REMOVAL).

(3) Using

ohmmeter,

check

for

continuity

between all of the blower motor resistor terminals. 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

WARNING: On vehicles equipped with airbags, dis-
able the airbag system before attempting any steer-
ing wheel, steering column, or instrument panel
component diagnosis or service. 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 air-
bag system. Failure to take the proper precautions
could result in an accidental airbag deployment and
possible personal injury or death.

WARNING: The blower motor resistor may get very
hot during normal operation. If the blower motor
was turned on prior to servicing the blower motor
resistor, wait five minutes to allow the blower motor
resistors to cool before performing diagnosis or
service. Failure to take this precaution can result in
possible personal injury.

(1) Disconnect and isolate the negative battery

cable.

(2) Reach under the instrument panel near the

blower motor and disconnect the wire harness con-
nector from the blower motor resistor (Fig. 19).

(3) Remove the two screws that secure the blower

motor resistor to the bottom of the HVAC housing
and remove the resistor.

Fig. 18 Blower Motor Resistor

1 - MOUNTING PLATE
2 - WIRE HARNESS CONNECTOR
3 - CERAMIC HEAT SINK

24 - 22

CONTROLS

BLOWER MOTOR RESISTOR BLOCK (Continued)

INSTALLATION

(1) Position the blower motor resistor into the

HVAC housing.

(2) Install the two screws that secure the blower

motor resistor to the HVAC housing. Tighten the
screws to 2 N·m (17 in. lbs.).

(3) Connect the wire harness connector to the

blower motor resistor.

(4) Reconnect the negative battery cable.

MODE DOOR ACTUATORS

DESCRIPTION

The floor/defrost and the panel mode door actua-

tors are reversible, 12–volt direct current (DC), servo
motors which mechanically positions the floor/defrost
and the panel mode-air doors. Both mode door actua-
tors are located near the drivers side end of the
HVAC housing.

Both mode door actuators are contained within a

black molded plastic housing with an integral wire
connector receptacle and three integral mounting
tabs that allow the actuators to be secured to the
HVAC housing. Both mode door actuators also have
an output shaft with splines that connects it to the
linkage that drives the respective mode-air door. The
mode door actuators do not require mechanical

indexing to the mode-air doors, as they are electron-
ically calibrated by the A/C-heater control.

OPERATION

The floor/defrost and the panel mode door actua-

tors are connected to the A/C-heater control through
the vehicle electrical system by a dedicated two-wire
take out and connector of the HVAC wire harness.
The mode door actuators can move the floor/defrost
and the panel mode doors in two directions. When
the A/C-heater control pulls the voltage on one side
of the motor connection high and the other connec-
tion low, the mode door will move in one direction.
When the A/C-heater control reverses the polarity of
the voltage to the motor, the mode door moves in the
opposite direction. When the A/C-heater control
makes the voltage to both connections high or both
connections low, the mode door stops and will not
move. These connections also provide a feedback sig-
nal to the A/C-heater control. This feedback signal
allows the A/C-heater control to monitor the opera-
tion and relative position of the floor/defrost and
panel mode doors. The A/C-heater control learns the
mode door stop positions during the calibration pro-
cedure and will store a diagnostic trouble code (DTC)
for any problems it detects in the mode door actuator
circuits.

NOTE: If battery voltage is low or not sensed at the
mode door actuator(s) for less than a 60 second
interval, the mode door actuator(s) will be out of
calibration. Remove fuse #3 BCM1 (I.O.D. fuse) for a
minimum of 60 seconds. The mode door actuator(s)
will then self calibrate upon reinstallation of the
fuse.

The mode door actuators can be diagnosed using a

DRBIII

t scan tool. Refer to Body Diagnostic Proce-

dures for more information.

The mode door actuators cannot be adjusted or

repaired and, if faulty or damaged, they must be
replaced.

REMOVAL

WARNING: On vehicles equipped with airbags, dis-
able the airbag system before attempting any steer-
ing wheel, steering column, or instrument panel
component diagnosis or service. 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 air-
bag system. Failure to take the proper precautions
could result in accidental airbag deployment and
possible personal injury or death.

Fig. 19 Blower Motor Resistor

1 - SCREW (2)
2 - WIRE HARNESS CONNECTOR
3 - HVAC HOUSING
4 - BLOWER MOTOR RESISTOR
5 - BLOWER MOTOR

CONTROLS

24 - 23

BLOWER MOTOR RESISTOR BLOCK (Continued)

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the instrument panel (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - REMOVAL).

(3) Disconnect the wire harness connector from the

floor/defrost and the panel mode door actuator, as
required (Fig. 20).

(4) Remove the three screws that secure each

mode door actuator to the HVAC housing and remove
the actuator, as required.

INSTALLATION

(1) Position the mode door actuators to the top of

the HVAC housing as required. If necessary, rotate
the actuator slightly to align the splines on the
actuator output shaft with those in the mode door or
linkage.

(2) Install the three screws that secure each mode

door actuator to the HVAC housing, as required.
Tighten the screws to 2 N·m (17 in. lbs.).

(3) Connect the wire harness connector to the

floor/defrost and panel mode door actuators, as
required.

(4) Install the instrument panel (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - INSTALLATION).

(5) Reconnect the negative battery cable.

RECIRCULATION DOOR
ACTUATOR

DESCRIPTION

The recirculation door actuator is a reversible, 12

volt direct current (DC), servo motor which mechan-
ically positions the recirculation-air door. The recircu-
lation door actuator is located on the left side of the
HVAC air inlet housing.

The recirculation door actuator is contained within

a black molded plastic housing with an integral wire
connector receptacle and three integral mounting
tabs that allow the actuator to be secured with three
screws to the air inlet housing. The recirculation door
actuator also has an output shaft with splines that
connects it to the linkage that drives the recircula-
tion-air door. The recirculation door actuator does
require mechanical indexing to the recirculation-air
door, as it is electronically calibrated by the A/C-
heater control.

OPERATION

The recirculation door actuator is connected to the

A/C-heater control through the vehicle electrical sys-
tem by a dedicated two-wire take out and connector
of the HVAC wire harness. The recirculation door
actuator can move the recirculation-air door in two
directions. When the A/C-heater control pulls the
voltage on one side of the motor connection high and
the other connection low, the recirculation-air door
will move in one direction. When the A/C-heater con-
trol reverses the polarity of the voltage to the motor,
the recirculation-air door moves in the opposite direc-
tion. When the A/C-heater control makes the voltage
to both connections high or both connections low, the
recirculation-air door stops and will not move. The
motor connections also provide a feedback signal to
the A/C-heater control. This feedback signal allows
the A/C-heater control to monitor the operation and
relative position of the recirculation door actuator
and the recirculation-air door. The A/C-heater control
learns the recirculation-air door stop positions during
the calibration procedure and will store a diagnostic

Fig. 20 HVAC Housing

1 - RECIRCULATION DOOR ACTUATOR
2 - RECIRCULATION-AIR DOOR
3 - HVAC HOUSING
4 - WIRE HARNESS CONNECTOR
5 - BLEND DOOR ACTUATOR
6 - WIRE HARNESS CONNECTOR
7 - FLOOR/DEFROST MODE DOOR ACTUATOR
8 - PANEL MODE DOOR ACTUATOR
9 - WIRE HARNESS CONNECTOR
10 - HVAC HOUSING MOUNTING BRACKET
11 - EVAPORATOR DRAIN TUBE
12 - HEATER CORE
13 - BLOWER MOTOR
14 - A/C EVAPORATOR
15 - HVAC HOUSING MOUNTING STUD
16 - HVAC HOUSING MOUNTING STUD

24 - 24

CONTROLS

MODE DOOR ACTUATORS (Continued)

trouble code (DTC) for any problems it detects in the
recirculation door actuator circuits.

NOTE: If battery voltage is low or not sensed at the
recirculation door actuator for less than a 60 sec-
ond interval, the recirculation door actuator will be
out of calibration. Remove fuse #3 BCM1 (I.O.D.
fuse) for a minimum of 60 seconds. The recircula-
tion door actuator will then self calibrate upon rein-
stallation of the fuse.

The recirculation door actuator can be diagnosed

using a DRBIII

t scan tool. Refer to the appropriate

diagnostic information.

The recirculation door actuator cannot be adjusted

or repaired and, if faulty or damaged, it must be
replaced.

REMOVAL

WARNING: On vehicles equipped with airbags, dis-
able the airbag system before attempting any steer-
ing wheel, steering column, or instrument panel
component diagnosis or service. 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 air-
bag system. Failure to take the proper precautions
could result in accidental airbag deployment and
possible personal injury or death.

(1) Disconnect and isolate the negative battery

cable.

(2) Remove the instrument panel (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - REMOVAL).

(3) Disconnect the wire harness connector from the

recirculation door actuator (Fig. 21).

(4) Remove the three screws that secure the recir-

culation door actuator to the HVAC air inlet housing
and remove the actuator.

INSTALLATION

(1) Position the recirculation door actuator to the

HVAC air inlet housing. If necessary, rotate the
actuator slightly to align the splines on the actuator
output shaft with those in the recirculation-air door.

(2) Install the three screws that secure the recircu-

lation door actuator to the air inlet housing. Tighten
the screws to 2 N·m (17 in. lbs.).

(3) Connect the wire harness connector to the

recirculation door actuator.

(4) Install the instrument panel (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - INSTALLATION).

(5) Reconnect the negative battery cable.

Fig. 21 HVAC Housing

CONTROLS

24 - 25

RECIRCULATION DOOR ACTUATOR (Continued)

Content .. 260 261 262 263 ..