A/C Performance Test
This procedure requires the technician to know what the actual relative humidity is for the time and day of the test. This information can be obtained from multiple sources, such as the internet or local news media.
Make sure the following conditions are met in the area where the test is to be performed:
NOTEWhen connecting service equipment couplings to the line fittings, verify that the valves of the couplings are fully closed prior to installation. This will reduce the amount of effort required to make the connection.
Maximum ambient temperature: 10°F (43.3°C)
- Connect a manifold gauge set or an A/C recycling/charging station.
Operate the heating-A/C system under the following conditions:
Engine at normal operating temperature
- Using a scan tool, manually close the high speed cooling fan relay. If this step is not performed, the test results will not be accurate.
Insert a thermometer in the driver side center panel air outlet and operate the A/C system until the thermometer temperature stabilizes or a minimum of 5 minutes.
NOTEThe compressor clutch may cycle while performing this test, depending upon the ambient temperature and humidity. If the clutch cycles, use the readings obtained before the clutch disengaged.
- With the A/C compressor clutch engaged, compare the observed panel outlet air temperature along with the ambient temperature of the work area.
Maximum Allowable Air Temperature at Center Panel Outlet:
Manifold Gauge Set
- A manifold gauge set may be needed with some recovery/recycling/charging equipment. The manifold gauge set should have manual shut-off valves, or automatic back-flow valves located at the service port connector end of the manifold gauge set hoses. This will prevent refrigerant from being released into the atmosphere.
Manifold Gauge Set Connections
LOW PRESSURE GAUGE HOSE - The low pressure hose (Blue with Black stripe) attaches to the suction (low side) service port. This port is on the A/C suction line located near the A/C expansion valve at the rear of the engine compartment.
HIGH PRESSURE GAUGE HOSE - The high pressure hose (Red with Black stripe) attaches to the discharge (high side) service port. This port is on the liquid line fitting located at the top of the receiver/drier near the right strut tower.
RECOVERY, RECYCLING, EVACUATION AND CHARGING HOSE
- The center manifold hose (Yellow, or White, with Black stripe) is used to recover, evacuate, and charge the refrigerant system. When the low or high pressure valves on the manifold gauge set are opened, the refrigerant in the system will escape through this hose.
When servicing the A/C system, an R-134a refrigerant recovery/recycling/charging station that meets SAE standard J2210 must be used. Contact an automotive service equipment supplier for refrigerant recovery/recycling/charging equipment. Refer to the operating instructions supplied by the equipment manufacturer for proper care and use of this equipment.