Cj Heater - Jeep 1979 CJ-5 Technical & Service Manual

30-1
HEATER
SECTION INDEX
Cherokee-Wagoneer-Truck Heater
3D-6 CJ Heater 3D-1
C J H E A T E R
Blower lofor
Control Cables
Defroster Duct
Fan Control Switch
Fresh Air Intake Duct
3D-4
30-4
30-5
30-4
3D-5
GENERAL
The blend-air type heater and defroster system is used
on all CJ vehicles. The blend-air method of heating uses
a constant flow system with engine coolant continuously
flowing through the heater core. The temperature of the
heated air entering the passenger compartment is con-
trolled by regulating the quantity of air which flows
through the heater core air passages, then blending it
WI P ERS W A S H E S
r « y MAX RIGHT
tnn OFF LEFT
AIR
OFF HEAT VENT
TEMP
DEF
6 0 3 5 7
Fig. 30-1 Heater and Defroster Controls
Fresh Air Ventilation
General
Heater and Defroster Operation
Heater Core
System Controls
Page
30-2
3D-1
30-2
30-4
30-1
with a controlled amount of cool, fresh air which by-
passes the heater core. System controls and operation
are described in this section.
When servicing a malfunctioning heater system, refer
to the Service Diagnosis for a list of the possible causes
and recommended service procedures.
SYSTEM CONTROLS
The heater and defroster controls consist of a fan
control switch and three push-pull knobs and cable as-
semblies which are located on the instrument panel (fig.
3D-1).
The air control is a dual function control. When the
control is pulled to the first position (Heat), it opens a
door in the fresh air inlet to allow air to enter the heater. •
When the control is pulled completely out (Vent), it
opens two additional doors (one in the left end of the
fresh air inlet and one on the right side of the heater) to
allow fresh air to enter the passenger compartment. A
new fresh air duct has been added to direct fresh air to •
the driver's side.
The defrost control knob operates a door in the heater
housing which regulates heater and defroster operation
by directing the flow of air through the defroster hose or
floor outlet.
The temperature control knob adjusts the amount of
airflow around the heater core and through the heater
core air passages. This regulates the degree of heat en-
tering the passenger compartment.
The fan control is a four-position control switch (Off,
Low, Med and High), which regulates the blower
motor and airflow for heat and defrost.