R-12 System

TEST PREPARATIONS

1. Do not park car in sunlight.
2. Ensure condenser and radiator are clean.
3. Drive belt is properly tensioned and in good condition.
4. Air ducts are properly installed and all cables properly adjusted.
5. A/C compressor clutch functions properly.
6. Connect pressure gauge set to service valves, then open all dash air outlets.
7. Run engine to operating temperature, then set engine speed at 2000 RPM.
8. Set blower to High, set control lever to Max-A/C and temperature lever to Cold.
9. Close windows and doors.

LEFTHAND VENT TEMPERATURE TO AMBIENT TEMPERATURE

1. Check the outside temperature against the vent output temperatures as follows:
a. At 68°F, 45-52°F.
b. At 77°F, 42-49°F.
c. At 86°F, 40-47°F.
d. At 95°F, 38-45°F.
e. At 104°F, 36-43°F.
2. If results do not fall within specifications, refer to HIGH PRESSURE CHECK and LOW PRESSURE CHECK.

Fig. 3 High Pressure Check Chart:

HIGH PRESSURE CHECK

Compare results with Fig. 3.
1. Letters on graph refer to the following:
a. A-high side discharge pressure.
b. B-ambient or outside temperature.
c. C-radiator cooling fan on low speed.
d. D-radiator cooling fan on high speed with switches Off.
e. E-radiator cooling fan on high speed with switches On.

Fig. 4 Low Pressure Check Chart:

LOW PRESSURE CHECK
Compare results with Fig. 4.
1. Letters on graph refer to the following:
a. A-low side suction side.
b. B-ambient or outside temperature.
c. C-A/C thermostat. Switch closes at upper level arrow, A/C compressor On. Switch opens at lower level arrow, A/C compressor Off.