Chevrolet Light Duty Truck 1973 Service Manual page 30

1 A-4 HEATER A N D AIR C O N D IT IO N IN G
Temperature Lever
This lever controls the positioning of the TEMPERA­
TURE door in the heater distributor assembly. All
incoming "outside" air is directed around the heater core
in the COLD position on through the core in the HOT
position. The desired outlet temperature is obtained by
blending heated and unheated air according to the
setting of the temperature lever.
Heater-Def Lever
The HEATER-DEF lever controls positioning of the AIR
and DEFROSTER doors in the heater distributor
assembly. In the OFF position, no air is allowed to enter
Fig. 4-Blower Motor Assembly
C O M P O N E N T PART REPLACEMENT
the system. Moving the lever to the right (toward
HEATER) opens the air door with the AIR door being
fully open at the HEATER position. Incoming air is
directed to the heater outlets (with slight air bleed to the
defroster outlets). Moving the lever between HEATER
and DEF, directs increasing amounts of air to the
defroster outlets until all air is directed to the defroster
outlets in the DEF position.
Fan Control
The blower fan lever is located on the left hand side of
the control assembly. When the lever is fully down, the
blower motor is inoperative. Moving the lever upward
actuates the three speed blower motor (LOW-MED-HI).
BLOWER MOTOR
Removal (Fig. 4)
1. Disconnect battery ground cable.
- Remove the battery.
G Models
2. Disconnect the blower motor lead wire.
3. Remove the five blower motor mounting screws and
remove the motor and wheel assembly. Pry gently
on the blower flange if the sealer acts as an
adhesive.
4. Remove the blower wheel to motor shaft nut and
separate the wheel and motor assemblies.
5. To install a new motor, reverse Steps l-4 above.
NOTE: The following precautions should be
taken to assure proper installation:
a. Assemble the blower wheel to the motor with
the open end of the wheel away from the blower
motor.
b. If the motor mounting flange sealer has
hardened, or is not intact, remove the old sealer
and apply a new bead of sealer to the entire
circumference of the mounting flange.
c. Check blower operation; blower wheel should
rotate freely with no interference.
HEATER DISTRIBUTOR AND CORE
ASSEMBLY
C-K Models
Replacement (Fig. 5)
1. Disconnect the battery ground cable.
2. Disconnect the heater hoses at the core tubes and
drain engine coolant into a clean pan. Plug the core
tubes to prevent coolant spillage at removal.
3. Remove the nuts from the distributor duct studs
projecting into the engine compartment.
LIGHT DUTY TRUCK SERVICE MANUAL