How your car's A/C works
Your A/C system moves heat out of the cabin using refrigerant, a compressor, a condenser in front of the radiator, and an evaporator behind the dash. If any part fails or refrigerant escapes, cooling drops off fast.
Low refrigerant (a leak)
A/C systems are sealed — if refrigerant is low, it leaked somewhere. Common leak points are O-rings, the condenser (hit by road debris), and the compressor shaft seal. Recharging without fixing the leak just buys a few weeks.
Compressor or clutch failure
If you hear clicking, grinding, or the clutch never engages, the compressor may be failing. In Texas, where A/C runs nine months a year, compressors work harder than anywhere.
Electrical and blend door issues
Blown fuses, bad relays, failed pressure switches, or a stuck blend door actuator can all cause warm air even with a healthy system. If one side blows cold and the other warm, a blend door is the likely culprit.
Why DIY recharge cans are risky
Store kits can overcharge the system, which raises pressures and damages the compressor. Some contain sealants that clog shop equipment and system components. A proper evacuate-and-recharge measures exactly the right amount.