System Performance Test - Temp & Pressure Relationships

Fig. 14 Air Conditioning Performance Test Chart. 1991-92 240SX:

1. Vehicle should be located in a shaded, well ventilated area.
2. Close all doors and leave drivers window open.
3. Open vehicle hood and connect gauge set to A/C system.
4. Insert a thermometer in the vent outlet, then determine relative humidity and ambient air temperature.
5. Position temperature lever to ``Cold,'' mode door to ``Vent,'' intake door to ``Recirc'' and fan speed to ``Max.''
6. Start engine and run at 1500 RPM for at least 10 minutes.
7. Compare discharge air temperature, high pressure reading and low pressure reading with the charts in Fig. 14.