Diagnostic Table
WARNING: This page is about a different variant/trim than selected.
- 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 High Fixed orifice tube - missing O-rings leaking/missing. 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.(2) Erratic operation or compressor not running A/C cycling switch - poor connection at A/C clutch connector or clutch cycling switch connector. A/C electrical circuit erratic - see appropriate 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
- Suction accumulator - refrigerant oil bleed hose plugged
- 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.