GMC 1982 Light Duty Truck Service Manual page 40

General D escription ................................................................ .........................
Control.............................................................................. .................................
Diagnosis...............................................................................................................
On Vehicle Service............................................................................................
Specifications.......................................................................................................
An auxiliary heater is available accessory to provide
additional heating capacity for the rearmost extremities of
the certain modles.
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. 1 A - 19.
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 w eather and
eliminate the radiant heat that would result.
1
Fig. A -l 8--Resistor -
AU XILIARY HEATER
INDEX
GENERAL DESCRIPTION
CONTROLS
W a te r V a lv e (Refer Fig. 1 A -l 1)
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 O F F position the valve is
closed to prevent unwanted heat during warm weather.
Fan Switch (Fig. 1A -2 0 )
located in the instrument panel, to the right of the steering
column.
G
Models
Two methods of control are employed with this system:
When heat is desired, and the fan switch is any position
The three speed fan switch ( L O W - M E D - H I ) is
HEATER 1A-15
1A-15
I A - 15
1A-17
1A-18
1A-20