when hvac is in auto the a/c turns on every time even if i set the temp so that only heat is needed. if i hit the a/c button to turn it off it kicks it out of auto mode. i had the dealer check it out today the said it was supposed to work like that but that doesn't make any sense. why would the a/c be running if you only need heat? thats terrible on the gas mileage. does everyones auto hvac work this way?