A/C Problem on 2004 Infiniti QX56

All fo a sudden the A/C is not cold and blowing warm air, what do I need to check first and I need help.

1 answer
Check to see if the compressor is getting voltage when it starts blowing warm air. If it has voltage, the compressor clutch is bad, if it isn't getting voltage, then you will need to diagnose the circuit, which can be quite complected. You should take it to a shop, just be sure that you can easily replicate the conditions when the problem occurs.