412-04-1 Control Components 412-04-1
DESCRIPTION AND OPERATION
Control Components Climate Control System Outputs
The electronic manual temperature control (EMTC) Blower Motor Resistor
system control components are used to select: The blower motor resistor adjusts the blower motor
• air inlet source (outside or recirculated). speed based on the blower motor switch setting.
• blower motor speed. The blower motor resistor contains 3 resistor coils
in series. The end of each resistor coil is wired to a
• discharge air temperature (temperature blend). setting in the blower motor switch. Voltage is
• discharge air location (defrost, panel, floor). available at the blower motor at all times when the
• A/C compressor operation. ignition is in the RUN position and then continues
to the blower motor resistor. The blower motor
Climate Control System Inputs switch will allow a path to ground with the addition
of 1, 2 or 3 coils in the blower motor resistor to
Climate Control Assembly (EMTC Module) the circuit. When the blower motor switch is in the
The climate control assembly integrates the MED HI position, the blower motor switch will add
temperature control, airflow mode selection, A/C a path to ground through 1 coil in the blower motor
request button, recirculated air request button and resistor. When the blower motor switch is in the
rear defog switch into a single unit. MED LO position, the blower motor switch will
The temperature control switch setting determines add a path to ground through 2 coils (in series) in
air temperature. Movement of the temperature the blower motor resistor. When the blower motor
display from COOL (blue) to WARM (red) causes a switch is in the LO position, the blower motor
corresponding movement of the temperature blend switch will add a path to ground through 3 coils (in
door and determines the air discharge temperature series) in the blower motor resistor. When the
that the air distribution system will maintain. The blower motor switch is in the HI position, the
temperature control switch is an integral part of the blower motor resistor is bypassed.
climate control assembly and cannot be installed Mode Door Actuators
separately.
The 3 airflow mode door actuators move the airflow
The A/C request button determines A/C compressor mode doors on command from the EMTC module.
operation, except when the function selected is in
the OFF, MAX or DEFROST mode. The A/C The panel/floor door and defrost door mode door
request button is an integral part of the climate actuators each contain a reversible electric motor
control assembly and cannot be installed separately. and a potentiometer. The EMTC module applies a
5-volt signal to one end of the potentiometer and
The recirculated air request button can select ground to the other. The potentiometer wiper is
recirculated air in any mode except DEFROST, and connected to the actuator output shaft and moves
fresh air in any mode except MAX A/C or OFF. with the output shaft. The voltage available at the
The rear defog button signals activation of the wiper indicates the position of the airflow mode
heated backlight. The rear defog button is an door. The actuator wiper voltage is sent to the
integral part of the climate control assembly and EMTC module which drives the actuator motor in
cannot be installed separately. whichever direction is necessary to make the
The EMTC module is not equipped with self-test actuator wiper voltage agree with the expected
capabilities. EMTC module wiper voltage value.
The air inlet mode door actuator is a reversible
Blower Motor Switch electric motor which moves the air inlet door
The blower motor switch is mounted in the climate between the outside and recirculated air inlets on
control assembly and controls blower motor speed command from the EMTC module. When RECIRC
by adding or bypassing resistors in the blower is requested, the air inlet mode door actuator moves
motor resistor in all modes except OFF. to the RECIRC position, allowing only recirculated
air inlet. When FRESH air inlet is requested, the air
inlet mode door actuator moves to the FRESH air
inlet position, allowing only outside air inlet.
Copyright ã 2004, Ford Motor Company
Last updated: 07/29/2004 2005 Mustang, 12/2004
412-04-2 Control Components 412-04-2
DESCRIPTION AND OPERATION (Continued)
Temperature Blend Door Actuator The temperature blend door actuator is located on
The temperature blend door actuator moves the the heater core and evaporator core housing.
temperature blend door on command from the
EMTC module.
The temperature blend door actuator contains a
reversible electric motor and a potentiometer. The
EMTC module applies a 5-volt signal to one end of
the potentiometer and ground to the other. The
potentiometer wiper is connected to the actuator
output shaft and moves with the output shaft. The
voltage available at the wiper indicates the position
of the temperature blend door. The actuator wiper
voltage is sent to the EMTC module which drives
the actuator motor in whichever direction is
necessary to make the actuator wiper voltage agree
with the expected EMTC module wiper voltage
value.
2005 Mustang, 12/2004
