A/C Performance Test

A/C PERFORMANCE
The A/C system is designed to remove heat and humidity from the air entering the passenger compartment. The A/C evaporator, located in the HVAC housing, is cooled to temperatures near the freezing point. As warm damp air passes over the fins in the evaporator, moisture in the air condenses to water, dehumidifying the air. Condensation on the evaporator fins reduces the A/C evaporators ability to absorb heat. During periods of high heat and humidity, an A/C system will be less effective. With the HVAC mode control set to RECIRC, only air from the passenger compartment passes through the A/C evaporator. As the passenger compartment air dehumidifies, A/C performance levels rise.

A/C PERFORMANCE TEST

WARNING: REFER TO THE APPLICABLE WARNINGS AND CAUTIONS FOR THIS SYSTEM BEFORE PERFORMING THE FOLLOWING OPERATION. FAILURE TO FOLLOW THE WARNINGS AND CAUTIONS COULD RESULT IN POSSIBLE PERSONAL INJURY OR DEATH.

Air temperature in test room and on vehicle must be 21° C (70° F) minimum for this test.

NOTE: When connecting the service equipment coupling to the line fitting, verify that the valve of the coupling is fully closed. This will reduce the amount of effort required to make the connection.

1. Connect a tachometer and manifold gauge set.
2. Set control to A/C, RECIRC, and PANEL, temperature lever on full cool and blower on high.
3. Start engine and hold at 1000 rpm with A/C clutch engaged.
4. Engine should be warmed up with doors closed and windows open.
5. Insert a thermometer in the left center A/C panel outlet and operate the engine for five minutes. The A/C clutch may cycle depending on ambient conditions. If the clutch cycles, unplug the low pressure cycling clutch switch wire harness connector from the switch located on the accumulator. Place a jumper wire across the terminals of the low pressure cycling clutch switch wire harness connector.
6. With the A/C compressor clutch engaged, compare the air temperature at the center panel outlet and the compressor discharge pressure to the A/C Performance Temperature and Pressure chart. The compressor clutch may cycle, depending upon the ambient temperature and humidity. If the clutch cycles, use the readings obtained before the clutch disengaged.

A/C Performence Temperature And Pressure - (Non-Turbo Engines Only):

A/C Performence Temperature And Pressure - (2.4L Turbo Engines Only):

A/C Pressure Diagnosis Part 1:

A/C Pressure Diagnosis Part 2:

A/C Pressure Diagnosis Part 3:

7. If the air outlet temperature fails to meet the specifications in the A/C Performance Temperature and Pressure chart, or if the compressor discharge pressure is high, refer to the A/C Pressure Diagnosis Chart.