Table Of Contents - GMC 1982 Light Duty Truck Service Manual

equipped with a catalytic converter, it will be necessary to warm the engine to
a normal operating tem perature before attempting to idle the engine for
periods greater than five (5) minutes. Once the choke is open and fast idle
speed reduced to a normal idle, diagnosis and adjustments can be made.
General Description............................................................ IB-1
C60 System (C-K & G M odels)................................... IB-1
Overhead Systems (C-K & G M o d e ls ) ...................... 1 B-3
System C o n tro l.................................................................. 1B-4
Motor Home Chassis S y ste m ......................................... 1 B-7
Diagnosis................................................................................ 1 B-9
Leak Testing The Refrigerant S y s t e m ..................... 1 B -11
Pressure Cycling System Diagnosis........................... 1 B-l 1
Compressor Diagnosis.................................................... 1 B-15
Insufficient Cooling......................................................... IB-15
Electrical System Diagnosis......................................... I B - 15
Evacuating and Charging Procedures.......................... IB-27
On Vehicle S erv ic e ........................................................... 1B-27
Air Conditioning System C a p a c ity ............................ 1 B-27
Checking O i l .................................................................... 1 B-27
Thermostatic Sw itch......................................................
Expansion V a lv e ............................................................. 1B-33
Engine Idle C om pensator............................................. IB-32
C o m p re sso r....................................................................... 1 B-33
C60 S y ste m -C -K M o d els............................................ 1 B-33
Condenser.......................................................................... IB-35
A ccum ulator-A ll........................................................... IB-35
Blower A ssem b ly .......................................................... 1B-35
Evaporator C ore............................................................ 1 B-35
Expansion T ube-A ll..................................................... 1 B-35
Selector Duct and Heater C o re ................................ 1 B-36
Kick Panel Air Valve................................................... 1 B-36
Plenum Air V a lv e ......................................................... 1 B-36
Control A s se m b ly ......................................................... 1 B-36
T em perature Door Cable A d ju s tm e n t................. 1 B-36
M aster Switch a nd/or Blower Sw itch..................... 1 B-36
Vacuum T a n k ................................................................ IB-37
Blower Resistor U n i t ................................................... 1 B-37
Blower Motor R e la y .................................................... 1 B-40
F u s e .................................................................................... IB-40
Overhead S y ste m -C -K M o d els.................................. IB-40
C 6 0 A /C SYSTEM
Both the heating and cooling functions are performed
by this system. Air entering the vehicle must pass through
the cooling unit (evaporator) and through (or around) the
heating unit, in that order, and the system is referred to as a
"re h e a t" system.
The evaporator provides maximum cooling of the air
passing through the core when the air conditioning system is
calling for cooling.
SECTION IB
AIR CONDITIONING
N O TIC E : W hen perform ing air conditioning diagnosis on vehicles
CONTENTS
IB-32
GENERAL DESCRIPTION
Rear D u c t ......................................................................... 1 B-40
Blower Motor R e s isto r................................................. 1 B-40
Blower Motor A ssem bly............................................... 1 B-41
Expansion V a lv e ......................... ................................. 1 B-41
Evaporator C o re............................................................ 1 B-41
Blower Motor Sw itch................................................... 1 B-43
F u s e .................................................................................. 1 B-43
C60 S y s te m -G M od els................................................
Condenser........................................................................ 1 B-43
A /C Air Distributor D u c t .........................................
A /C Center and Right Dash Outlets,
Heater, Air Distributor and Extension Ducts .... 1 B-43
H eater Core Case and C o r e ...................................... 1 B-44
Blower M o to r................................................................. 1 B-45
Evaporator C ore............................................................ 1 B-45
Temperature Door C able............................................ 1 B-45
C o n tro l............................................................................ 1 B-45
Blower S w itc h ................................................................ 1 B-46
Blower Motor R e la y .................................................... 1 B-46
Resistors.......................................................................... 1 B-46
Blower Motor R e la y .................................................... 1 B-46
Vacuum T a n k ................................................................ IB-51
Circuit B reak er............................................................. IB-51
Overhead S y s te m -G M o d els...................................... 1 B-51
Dash Mounted S y ste m -M o to r Home U n its ..........
Condenser........................................................................ IB-51
R eceiver-D ehydrator................................................... 1 B-51
Sight G la ss..................................................................... 1 B-52
Blower-Evaporator A ssem bly.................................... 1 B-52
Blower A ss e m b ly .......................................................... 1 B-53
Expansion Valve, Evaporator Case or C o r e ......... 1 B-53
Thermostatic an d/or Blower Switches.................... 1 B-53
R e sis to r........................................................................... 1 B-53
F u s e .................................................................................. 1 B-54
Specifications..................................................................... 1 B-54
Special Tools......................................................................
On C-K and G Series, compressor operation is
controlled by a pressure sensing switch, located near the top
of the accumulator. The switch responds to pressure changes
to turn the compressor ON or O FF, as required.
System operation is as follows:
Air, either outside air or recirculated air, enters the'
system and is forced through the system by the blower. As
AIR CONDITIONING IB-1
1 B-43
1 B-43
IB-51
IB-55