Chevrolet Light Duty Truck 1973 Service Manual page 107

THIS SYSTEM DOES N O T H A V E A SIG H T GLASS. UNDER N O
NOTE
CIRCUMSTANCES SHOULD A SIGHT GLASS BE INSTALLED
Feel Liquid Line Before Expansion Tube
Cold
Restriction in High Side of System.
Visually Look For Frost Spot to
Pipes same Temperature or
Locate Restriction, Repair, Evacuate
Outlet Colder Than Inlet
-----------------1 ------------------
Charge and Check The System
I
Install the Thermometer in A / C O utlet and
Check Performance-See Performance Test
System
and Performance Data O utlined Earler in
( O K .)
This Section I
Outlet Temperature Satisfactory or Outlet Temperature High -
too cold - See Performance Data See Performance Data
Check Accumulator Pressure
( See Performance Data)
Change Blower Speed To Low,
and O bserve Accumulator and
Lov
Evaporator Pipes For Frost.
Plugged Expansion Tube.Repair
or Replace and Evacuate, Charge
I
and Check System.
I
Frost
N o Frost
System
(OK.)
System Defective Thermostatic
( O K.)
I
Switch
I
Replace
| M issing""}1
System
Install Expansion Tube, Evacuate,
( O K .)
Charge and Check System.
System
( O K.)
i
INSUFFICENT C O O L IN G -F O U R SEASON SY STEM (C-K M ODELS)
M ove temperature lever rapidly back and forth from max
heat to max. cold Listen for temperature door hitting at each end
Hitting
1 Set Temperature Lever at Detent to the Right of Cold
2 Set Selector Lever at A / C
3. Set Blower Switch on High
4. O pen Doors and Hood
5 W arm Engine
6 Run Engine at ldle( Except 06 Models)
1000 RPM ( C -K 06 Models)
Feel For Air Flow A t Heater And A / C Outlets
A ir Flow From
A / C Outlets O nly
I
Check Visually For Compressor Clutch O peration
______________________ _ _____________________
Engaged or Cycling
I
W a rm l
Feel Evaporator Inlet and Accumulator Outlet Pipes
Inlet Pipe Colder
Than Outlet Pipe
Leak Check System-Repair Leak If No
Leak is Found, Check Expansion Tube
For Plugged Filter Evacuate and Charge
System. Check Inlet & O utlet Pipe Temperatures.
Pipes Still Cold and
W arm as A bove
Replace Expansion Tube
and Evacuate, Charge and
High To Normal
I
Check System
System
(O K .)-
Check Compressor Cycling
O n Continuously Cycles on and O ff
Defective Thermostatic Switch
Check For Missing Expansion Tube
r
^ In Place
Check Compressor
Inlet Screen I
Plugged Clean
T
Repair or Replace Screen, E vacuate, System O ver-C harged.P urge,
i i
Charge and Check System,
Evacuate, Charge and Check System,
System
System
( O.K.)
( O K .)
Fig. 100--lnsufficient Cooling Diagnosis-C-K Four-Season System
| Not Hitting I
Adjust Door
Outlet
Some or All A ir Flow From Heater
Check M ode Door O peration-Repair,
Check Compressor Hot Lead W ire W ith Test
Light or Place a Jumper W ire From The
Compressor to The Positive ( +) Terminal of
The Battery.
| N ot Engaged
A p p ly External G round to Compressor,
IL
if Clutch is Still not Engaged , Replace
Compresor Clutch - See the
O veraul Manual j
T
System
( O K . )
1
Discharge
Pressure Switch
Pipes Same Temperature ( Cold)
or O utlet C older Than Inlet
Check Refrigerant Pressure
System
at High Side Fitting
( O K .)
( At Pressure Switch)
r
Below 50 PSIG
| A b o ve 50 PSIG _ __ _
Jump Switch Lost Charge -
I
Leak Test and
i
Compressor Runs
Repair. Evacuate,
Charge and Check System,
D efective Switch
I
Leak Check System,
l
Replace
Replace Switch, Evacuate,
System
Charge and Check System. I
( O K .)
System
( O K .)
O ff All the Time ---1 -------
I_________________
|
Engaged
Check For Blown M ain Fuse
I
Check For O p e n Circuit
at the Follow ing t
Thermostatic
Switch
r
D efective
I
Switch
I
Replace
System
( O K .)
i
System
( O K .)