Diagnostic Table

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The following table is used to guide diagnosis of the refrigerant system if operating pressures are outside normal limits.

Refer to the chart below.

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.
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).
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 A/C Electrical Circuit Wiring Diagram.
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