Auto A/C system Air Flow

No air flow

1. Inspect blower motor
2. Inspect blower motor resistor
3. Inspect fuse
4. Inspect A/C climate control
5. Inspect connectors
6. Inspect harness
7. Inspect hvac box for

Automotive Cooling system

No cooling

1. Inspect A/C switch
2. Check refrigerant level
3. Inspect clutch relay
4. Inspect PCM/BCM/ECM
5. Inspect A/C pressure switch
6. Inspect compressor clutch coil
7. Inspect compressor clutch
8. Inspect compressor clutch air gap
9. Inspect condenser
10. Inspect condenser fan
11. Inspect radiator fan
12. Inspect evaporator temperature control devices
13. Inspect temperature sensors control devices
14. Inspect climate control
15. Inspect in cabin temperature sensors
16. Inspect sun load sensors
17. Inspect power steering pressure sensor

Auto a/c system diagnosis by Smell

1. Check cabin air filter
2. Check evaporator core
3. Check hvac box drain tube
4. Check re-circulation air door /actuator
5. Check hvac box seals

Auto a/c system diagnosis by Noise

Clicking noise

1. Check A/C clutch
2. Inspect A/C clutch relay
3. Inspect cycling switch
4. Inspect refrigerant level
5. Inspect evaporator temperature sensor

Squealing

1. Check drive belt
2. Check belt tensioner
3. Check compressor for seizing

Grinding

1. Check compressor
2. Check compressor clutch

Other helpful tips

Replace the receiver driver with every A/C service.
Replace cabin air filter annually
Ensure that service valve caps are in place at every A/C service.