I have a 2004 Lariat Supercrew with temp control A/C. Most of the time when I turn on A/C and it's set at 70 or lower and outside temp is above 80, it blows hot. Not AC not working hot, but more of the heat is on with the ac. If I move the temp up to 90 (max) wait a couple seconds, then bring it back down to 70 or lower, it blows cold. Is there an internal sensor for the temp somewhere in the cab?