Chevrolet 1980 Light Duty Truck Service Manual page 43

General Description........................................................................... I A-15
Control............................................................................................... 1A-15
Diagnosis
On Vehicle Service.............................................................................
Specifications....................................................................................... 1 A-19
An auxiliary heater is available as a dealer installed
accessory to provide additional heating capacity for the
rearmost extremities of the G (05 and 06) models.
This unit operates entirely independent of the standard
heater and is regulated through its own controls at the
instrument panel.
This system consists of a separate core and fan unit
mounted as shown in Fig. 1A-23.
Heater hoses extend from the unit to the front of the
vehicle where they are connected to the standard heater
hoses with "tees". An "on-off" vacuum operated water
valve is installed in the heater core inlet line in the engine
compartment. The purpose of the valve is to cut off coolant
flow to the auxiliary core during warm weather and
eliminate the radiant heat that would result.
AUXILIARY HEATER
INDEX
GENERAL DESCRIPTION
except off, a vacuum operated water valve controlled by the
switch, opens the water line to permit hot water circulation
through the heater core. In the OFF position the valve is
closed to prevent unwanted heat during warm weather.
in the instrument panel, to the right of the steering column.
CONTROLS
Two methods of control are employed with this system:
W a te r Valve (See Fig. 1A-11)
When heat is desired, and the fan switch is any position
Fan Sw itch (Fig. 1A-20)
The three speed fan switch (LOW-MED-HI) is located
HEATER 1A-15
1A-17
LIG H T T R U C K SERV ICE M ANUAL