i have a 99 acura tl and the control that switches from hot to cold or from heater to ac temperatures only stays on cold and when i try to go to hot it just stays cold so when my heater is on it still only blows cool air. it happened before and then it worked but now it just stays cold whether i have it on hot or cold. i'm reffering to the round *** that goes from 60 to 90 degrees. even when it is at 90 degrees it is still coming out as if it is stuck on 60 degrees. please help someone


thankyou