Diagnostic Table
WARNING: This page is about a different car, the 2010 Lincoln MKX and 2010 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
- Refer to the chart below.DIAGNOSTIC CHART
High (Discharge) Pressure Low (Suction) Pressure Component - Causes High or Clutch Cycling High Condenser - inadequate airflow. High Normal to High Engine - overheating. Normal to High Normal Refrigerant overcharge - air in refrigerant. Normal to Low Normal to High A/C suction line - partially restricted or plugged. (1) Normal to Low Low or Clutch Cycling Low refrigerant charge, A/C suction line - partially restricted or plugged A/C cycling switch - sticking closed (if equipped). (2) Erratic Operation or Compressor Not Running Evaporator discharge air temperature sensor or A/C pressure transducer - poor connection at A/C clutch connector. A/C electrical circuit erratic - see SYSTEM WIRING DIAGRAMS for Edge or SYSTEM WIRING DIAGRAMS for MKX, A/C Electrical Circuit . Normal to Low High Compressor - low performance. Additional Possible Cause Components Associated With Inadequate Compressor Operation - Compressor Drive Belt - loose
- Compressor Clutch - slipping
- Clutch Coil Open - shorted, or loose mounting
- Control Assembly Switch - dirty contacts or sticking open
- Clutch Wiring Circuit - high resistance, open or blown fuse
- Compressor Operation Interrupted by Engine Computer
Additional Possible Cause Components Associated With a Damaged Compressor - Incorrect Clutch Air-gap
- Refrigerant Leaks
(1) Low pressure reading will be normal to high if pressure is taken at accumulator and if restriction is downstream of service access valve. (2) Low pressure reading will be low if pressure is taken near the compressor and restriction is upstream of service access valve.
NOTE:
The following table is used to guide diagnosis of the refrigerant system if operating pressures are outside normal limits.