TM 9-4120-388-14
5-13. REFRIGERANT PRESSURE CHECK.
Except in cases where it is obvious that the refrigerant charge has been lost, the first step in troubleshooting problems
in the refrigerant system should be to check discharge and suction pressures under operating conditions. Check pressures
as follows:
a. Turn the mode selector switch to OFF.
b. Remove four screws and flat washers from service valve access cover.
c. Remove protective caps from service valves.