Hey Scotty, sorry for the long post. I'm in Houston and it's been pretty hot lately.
My AC in my automatic rebuild 2014 Mazda 3 was acting up for the last 2 months. The AC clutch engages and stays on the entire time when it wouldn't work and it would cycle on and off when it was working fine. It would blow warm mostly on hot days. The compressor also makes this noise when it turns on which I assume is normal but it also makes this low whining noise (not too loud) only when you press the gas pedal. At highway speeds the sound is not there, just during first and second gear or if I'm parked and I press on the pedal.
Anyway I went to pepboys and 130 dollars later they said the car was missing 5oz of freon so they topped it and now the AC is ice cold but the sound is still there.
Is my compressor on it's way out?
I attached a video from inside the car. At around 2 seconds the AC kicks in and notice when I press on the pedal how you can hear that whining noise that abruptly stops when the compressor shuts off.