Last year my car AC stopped working at sudden. Only fan was running.
He took 2 hours to find the issue. Gas, Leakage, Buttons, Pipes, Inner/Outer wirings, Fuses, Joints, Grips, etc. etc.
Eventually he found that AC’s Thermostate switch is faulty which is hidden under the dash board.
He replaced the switch cost was 250 only.
But I paid him well for all his work to find it.
If I have it checked with some usual AC technician, then it can be a nightmare.