GMC 1986 P-Truck Service Manual page 74

INSUFFICIENT COOLING-A/C SYSTEMS WITH CYCLING CLUTCH- EXPANSION TUBE (PRESSURE SENSING)
4 Inlet Pipe Colder Than Outlet P ip T j
| Leak Check System |
No Leak Found |
Add 1 Lb Of Refrigerant— 12
Then Check Clutch Cycle Rate
| Above 6 Cycles Per Minute | | 8 Cycles Per Min. Or Less |
"D isc h arg e System And
Check For Plugged Orifice
— zzxiiz:
| Evacuate & Charge |
| System (O.K.) |
Inlet And Outlet Same Tem p..
Or Outlet Colder Than Inlet
Add One More Pound Of
Refrigerant— 12____
Inlet & Outlet Pipes ngain
| System (O .K .)|
I
Inlet And Outlet Same Temp.,
Or Outlet Colder Than Inlet
Add One More Pound Of
Refrigerant — 12
| System (O.K.
Figure 12—Pressure Cycling System Diagnosis (Cont.)
Attach Fused Jum per Wire From Compressor Hot Lead To Positive ( + )
_____________ Battery Post And Check Compressor Operation
Apply External Ground To Compressor,
If Clutch Is Still Not Engaged Removed
Clutch & Repair As Per Service Manual
| System (O.K.) |
Leak
Found I
I '
I Repair As Necessary I
' I 1
| Evacuate & Charge |
\
| System (O.K.)
| Above 345 kPa (50 PSI) |
"D isc h arg e System
And Check For Plugged
Feel Inlet & Outlet Orifice Or High Side
Restriction
Pipes Again
Repair Or Replace
Evacuate & Charge
Inlet Pipe Colder
Than Outlet Pipe
T '
_ '
| Inlet Pipe Colder" Than Outlet Pipe |
' Discharge System And Check
For Plugged Orifice
| Evacuate & Charge |
| System (O.K.) |
AIR CONDITIONING
J i
Off A lim s Time
I Engaged
Remove Jumper And Check Refrigerant
Pressure At Accumulator Fitting
\
| Below 345 kPa (50 PSI)
Above 345 kPa (50 PSI) !
Check High Side Refigerant
Pressure
Check For
Open Circuit,
Broken Wire,
etc. Repair
X
As Necessary
I
System
I
( O K . )
| Below 345 kPa (50 PSI) I
Lost Charge
Leak Test & Repair
Evacuate & Charge
I
System
(O. K. )
1B -1 1
Jump Pressure Switch
Does Compressor Run
Replace
*Do Not Discharge
System. There Is A
Schrader Valve
I
System
(O.K.)
F-00163