Temperature Lever - Chevrolet 10 1971 Series Chassis Service Manual

HEATER AND AIR CONDITIONING 1A-8
TO
CENTER DASH
OUTLET
TO
BALL
DASH
OUTLETS
TO
DEFROSTER
OUTLETS
FLOOR
OUTLET
The evaporator provides maximum cooling of the air
passing through the core when the air conditioning sys­
tem is calling for cooling. The control valve acts in the
system only to control the evaporator pressure so that
minimum possible temperature is achieved without core
freeze-up. The valve is preset, has no manual control,
is automatically altitude compensated, and non-repairable.
System operation is as follows (See Figure 14): Air,
either outside air or recirculated air enters the system
and is forced through the system by the blower.
The air passes by the temperature door and is directed
through the heating or cooling cores, or split to flow
through both. After flowing through the core or cores,
the air passes the outlets door which directs it to the
dash or floor outlets or both.
outlets is finally controlled by the position of the air
outlets. Air directed to the floor outlets passes the
defroster door which directs the air out the floor outlets,
the defroster outlets, or both.
Linkage is so designed that when the system controls
are calling for heat, air will enter the vehicle through the
floor distributor duct, and when the system controls call
for cooling, air will enter through the three dash outlets.
The side dash outlets may be rotated to provide either
soft, diffused airflow or spot cooling. Rotate half way to
shut off airflow. The barrel type outlet in the center of
the dash will direct air up or down or, if desired, shut it
off.
CONTROLS
Full control of the Four-Season System is obtained
through the use of a single control panel (fig. 13). The
control levers make use of bowden cables to activate the
\ DEFROSTER
DOO R
Fig. 14— Airflow Schematic
Air directed to the dash
EVAPORATOR
CORE
HEATER
CORE
various doors and switches necessary for system opera­
tion. Control adjustment is a matter of properly setting
these bowden cables. The following paragraphs explain
each control.
"Outlet" Lever
This lever actuates an air diverter door within the duct
assembly which routes airflow when fully right (HEATER)
to the floor distributor ducts (for heater operation) or
when fully left (A/C) to the dash outlets (for cooling
operation).
Moving this lever toward the left from the HEATER
position will activate the compressor clutch switch and
set the cooling portion of the system in operation pro­
viding the FAN switch is turned on.
When the lever is moved fully toward the right (heating
position) the AIR control lever will automatically move
to the outside air position.

Temperature Lever

The "TEMPERATURE" lever, through its bowden cable,
actuates the door which controls outlet temperature.
This door is necessary to permit mixing of hot and cool
air to provide the desired conditioned air outlet tempera­
ture, whether during heating or cooling operations.
The temperature door directs the airflow through
either the heater core, the evaporator core or through
both. When the system is set for full cooling, all air
passes through the evaporator core. When warmer out­
let air is desired, the temperature door is moved by the
temperature lever so that some air passes through the
heater core. The warmed air mixes with the cooled air
resulting in a higher outlet air temperature. In the full
HOT position, all air flows through the heater core.
OUTSIDE
AIR
INLET VALVE
BLOWER
ASSEMBLY
RECIRCULATING
AIR INLET
VALVE
10-30 CHEVROLET TRUCK SERVICE MANUAL
For