2007 Hyundai Sonata. Two weeks ago I took it in because the A/C just wasn't cooling properly. A necessity in 95+ heat here in Bama. I was pretty sure it just needed coolant as it had been a while since it had been serviced. They topped it off and put dye in it to check for leaks. Well, naturally, yesterday when the temps hit 100 and I had an hour's drive, it went out completely. I'll take it back on Wed (first day I can get it there), but I'll take ideas on what's gone. My guess is the compressor, but who knows. Thoughts?