Chevrolet 1977 light duty truck, Service Manual

Page: 88 / 861

2. Purge the system o f refrigerant.
3. Disconnect the w iring harness at the switch.
4. Remove the switch from the refrig eran t line.
5. To replace, reverse Steps 1-4 above.
N O TE: Be sure to use new " O " rings, coated with
clean regrigeration oil, w hen installing the switch.
6. Evacuate charge an d check system operation.
FUSE
A 25 a m p fuse, located in the junction block protects
the entire air conditioning system except for the blower
circuit, the fuse for the blower circuit is located in the
electrical w iring between the junction block and the
blower relay (fig. IB-45).
OVERHEAD SYSTEM--C-K
MODELS
T h e Overhead System is used in conjunction with
the F our-Season System. Since replacem ent o f Four-
Season System com ponents has been covered previously,
only those com ponents peculiar to the O verhead System
will be covered in this section.
REAR D U C T
This duct covers the blower-evaporator assembly, at
the rear o f the vehicle, and incorporates four adjustable
air outlets (fig. IB-46).
Replacement
1. Disconnect the battery gro u n d cable.
2. Disconnect the d ra in tube from the rear duct.
3. Remove the screws securing the duct to the roof
panel and re a r h e a d e r brackets.
4. Remove the duct.
5. To install, reverse Steps 1-4 above.
BLOWER M O T O R RESISTO R
The blower m otor resistor is located on the cover
side o f the Four-Season System blower-evaporator as
shown in Figure IB-47.
Replacement
1. Disconnect battery ground cable.
2. Disconnect the electrical harness at the resistor.
3. Remove the resistor attaching screws and
remove the resistor.
4. To install a new resistor, reverse Steps 1-3
above.
BLOWER M O T O R ASSEM BLY
Removal (Fig. IB -4 8 )
B L O W E R M O T O R
B L O W E R R E S IS T O R
y
L IN E
D I S C H A R G E PR ESSUR E
S W I T C H
J U N C T I O N B L O C K
C O M P R E S S O R