2006 mega cab 5.9 with AC that works great up to about 80 out side temperature then blows hot. I’ve been to the dealer 3 times and of course it’s never hot enough to cause the ac to stop. Dealer says system is charged, functioning, and there are no codes. When the ac does stop blowing cold the compressor or clutch is not working. Is this a sensor, or computer, or something else?