Chevrolet 1977 light duty truck Service Manual page 59

SELECTOR
LEVER COMPRESSOR
POSITION
OFF
OFF
ON
M A X A/C
NORM A/C ON
ON
B I-LE VEL
VE NT OFF
HTR OFF
DEF ON
NOTE % 100% Inside air is not availab e, some bleed through o f outside air is allowed.
O VERHEAD SYSTEM (C-K MODELS)
This system operates in conjunction with the Four-
Season System. Since refrig eran t flow is controlled by the
front system, the only control provided for on the
overhead system is a three-speed fan switch (LOW,
MED, HI). T he fan switch is mounted in the instrum ent
panel, to the right o f the steering coloumn (fig. IB-13.
In the O F F position, the blower is inoperative;
S Y S T E M O P E R A T IO N - C K T R U C K
BLOWER
AIR
SPEEDS
SOURCE
A V A IL
LOW OUTSIDE
HI INSI DE%
A L L OUTSIDE
A L L OUTSIDE
A L L OUTSIDE
A L L OUTSIDE
A L L OUTSIDE
Fig. 1 B 1 1 -S yste m Operation - CK Truck
Fig. 1B- 12 -Air C o n d itioning Vacuum Schematic - CK Truck
AIR
HEATER A/C
ENTERS
VEHICLE
FLOOR OUTLETS
DASH OUTLETS
DASH O UTLETS
FLOOR AND
DASH OUTLETS
DASH OUTLETS
FLOOR OUTLETS
DEFROST OUTLETS
however, refrigerant is circulating in the system if the
Four-Season System is ON. In any o f the three blower
positions (LOW, MED, HI), the blower will be operative
regardless if the Four-Season System is ON.
N OTE: To o btain m axim um cooling, the Four-
Season System should be on A /C , temperature
HEATER
DOOR- DEFROSTER
OPEN TO: DOOR-OPEN TO:
HEATER
HEATER
A/C HEATER
HEATER
A/C
A /C &
HEATER
HEATER
A/C HEATER
HEATER HEATER
HEATER DEFROST