AC failure after long drive compressor?

[familyintow]

So, I was on this long highway drive for about four hours, and then suddenly, my AC stopped working. At first, I noticed this weird faint whining noise, and before I knew it, warm air started creeping in. I checked around and couldn't see any leaks. Could it be the compressor, I wonder?

 

[BBQsteven]

That whining noise is often the compressor whining, but that's not always the case. It could also be the clutch or the cooling fan. Have you tried running the AC after that to see if it sounds the same?