A/C compressor clutch and coil

How you know it is this

• The pulley spinning but the compressor centre not turning
• No click from the engine bay when the air conditioning is switched on
• Cold air that comes and goes
• A rattle from the pulley with the system off

Worth knowing before you buy

• Much cheaper than a compressor, and a very common failure. Always ruled out first.
• Watch the centre of the pulley with the system switched on: if the pulley turns and the centre does not, it is the clutch.
• No engagement at all is often the pressure switch or low gas, not the clutch — the system refuses to engage to protect itself.
• The air gap is adjustable on many clutches and a worn one can sometimes be shimmed.

Rest of the refrigerant circuit

• A/C compressor
• Condenser
• Receiver drier / accumulator
• Expansion valve
• A/C pipes and hoses
• Pressure switches and sensors
• Evaporator
• Refrigerant and oil