75R7290 | York® A/C Compressor With Pulley

1. Compress Refrigerant Gas

The compressor takes in low-pressure refrigerant vapor from the evaporator inside the cabin.
It compresses it into high-pressure, high-temperature gas.
This step is essential because refrigerant must be pressurized to release heat in the condenser.

2. Circulate Refrigerant Through the System

The compressor pushes refrigerant through the A/C loop:
Evaporator → Compressor → Condenser → Expansion Valve → Back to Evaporator
Without the compressor, nothing moves—and the system doesn’t cool.

3. Enable Heat Transfer

Once pressurized by the compressor, the hot refrigerant flows to the condenser, where it releases heat to the outside air.
Then it cools down, turns into a liquid, and absorbs heat from the cabin air in the evaporator.

1. No Cold Air from Vents

The most obvious sign.
If the compressor isn't working, refrigerant doesn't circulate → no cooling.

2. Compressor Clutch Not Engaging

(Applies to belt-driven compressors with a clutch)
The clutch allows the compressor to engage or disengage.
If it fails:
No cold air.
Clutch might not spin even when A/C is turned on.
You may hear a click (or not) when it tries to engage.

3. Strange Noises

Grinding, squealing, knocking, or rattling when A/C is on.
Could indicate:
Worn bearings
Internal damage (pistons, seals)
Clutch failure

4. Refrigerant Leaks

Look for oil or dye stains around the compressor body or fittings.
Leaking refrigerant can lead to:
Low system pressure
Compressor damage from running dry

5. Circuit Breaker or Fuse Blown

Compressor may pull too much electrical current when failing.
If the A/C fuse keeps blowing → compressor clutch or coil may be shorted.

6. High Cabin Temperatures

Air from vents is warm, even when A/C is on full.
Could be:
Compressor not working
System not building pressure
Blockage or restriction due to failed compressor

7. Dashboard Warning Light / A/C Trouble Code

Some modern vehicles can detect A/C system faults and trigger:
Warning light
Diagnostic trouble code (e.g., P0530–P0533 = A/C pressure sensor faults)

8. Visible Damage

Cracks or dents in compressor housing
Burn marks on clutch
Frayed wires