Check that the AC is turned on and set to the coldest temperature
Set the fan to a higher speed
Make sure the recirculation mode is on
Check the AC fuse and replace it if blown
Inspect the AC relay and replace it if faulty
Check the cabin air filter and replace it if clogged
Inspect the refrigerant level and recharge if low
Look for refrigerant leaks and repair them
Check the AC compressor for proper operation
Inspect the compressor clutch for engagement
Check the serpentine belt for damage or looseness
Inspect the condenser for blockage or damage
Clean debris from the condenser and vents
Check the cooling fans for proper operation
Inspect AC hoses and connections for leaks
Test the pressure switches and replace if faulty
Check the expansion valve or orifice tube for blockage
Inspect the evaporator for freezing or blockage
Verify the blend door is working correctly
Reset the climate control system if applicable
Have a certified mechanic diagnose electrical or compressor issues