I just recently purchased my 2006 Mega Cab 5.9 auto truck. The air blows strong and it works great, usually. Twice now, when I have adjusted the temp to compensate for early morning coolness, the A/C will stop working for the remainder of the day. The only thing I do is turn the temp slightly. At that point the compressor will stop working. Today, it did it at 8:30 this morning and I shut the truck off 10x or more and restarted it. It did not work again until I left it off for a few hours, with it working fine when I restarted it. I am thinking it is the heater control switch. Let me know your thoughts.