System Performance Check

CAUTION: Use only an R-12 refrigerant Air Conditioning Service Station.

The performance test will help determine if the air conditioning system is operating within specifications.


1. Connect an Air Conditioning Service Station as shown.







2. Insert a thermometer in the center vent outlet. Determine the relative humidity and ambient air temperature by calling the local weather information line.
3. Test conditions:
- Avoid direct sunlight.
- Open hood.
- Open front doors.
- Button type: Set the temperature control knob to COOL and push dash VENT and RECIRCULATE buttons.
- Lever type: Slide the temperature control lever to COOL and the mode control lever to VENT and push RECIRCULATE button.
- Turn the heater fan switch to MAX.
- Turn the A/C switch ON.
- Run the engine at 1,500 rpm.
- No driver or passengers in vehicle.
4. After running the air conditioning for 10 minutes under the above test conditions, read the delivery temperature from the thermometer in the dash vent and the high and low system pressure from the Air Conditioning Service Station.

Delivery Temperature Chart:

5. To complete the charts:
- Mark the delivery temperature along the vertical line.
- Mark the intake temperature (ambient air temperature) along the bottom line.
- Draw a line straight up from the air temperature to the humidity.
- Mark a point one line above and one line below the humidity level (10% above and 10% below the humidity level).
- From each point, draw a horizontal line across to the delivery temperature.
- The delivery temperature should fall between the two lines.
- Complete the low side pressure test and high side pressure test in the same way.
- Any measurements outside the line may indicate the need for further inspection. Pressure Test Chart

A/C Pressure Troubleshooting:

PRESSURE TEST CHART