A/C System Test
Performance Test
  • Compressed air mixed with the R-134a forms a combustible vapor.
  • The vapor can burn or explode causing serious injury.
  • Never use compressed air to pressure test R-134a service equipment or vehicle air conditioning systems.

  • Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
  • Be careful when connecting service equipment.
  • Do not breathe refrigerant or vapor.

The performance test will help determine if the air conditioner system is operating within specifications.
Use only service equipment for refrigerant HFC-134a (R-134a).
If accidental system discharge occurs, ventilate the work area before resuming service.
R-134a service equipment or vehicle air conditioning systems should not be pressure tested or leak tested with compressed air.
Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
  1. Connect an R-134a refrigerant recovery/recycling/charging station to the high-pressure service port and the low-pressure service port, following the equipment manufacturer's instructions.
  1. Determine the relative humidity and air temperature.
  1. Remove the passenger's dashboard trim, then remove the glove box.
  1. Insert a thermometer (A) in the center vent.
  1. Place another thermometer (B) near the blower unit's recirculation inlet duct.
  1. Test conditions:
    • Avoid direct sunlight.
    • Open hood.
    • Open front doors.
    • Set the temperature control dial to Max Cool, the mode control switch to Vent, and the recirculation control switch to Recirculate.
    • Turn the A/C switch ON and the fan switch to Max.
    • Run the engine at 1,500 rpm (min −1 ).
    • No driver or passengers in vehicle.
  1. After running the air conditioning for 10 minutes under the above test conditions, read the delivery temperature from the thermometer in the center vent, the intake temperature near the blower unit, and the high and low system pressure from the A/C gauges.