i have re-calibrated the hvac in the van without any errors. i am still getting an issue at time where the temp control is set to coll but it still blows out hot air. if i get lucky i can turn the control to warm and then back again and it will cool down but at times i may have to do this several times. Sometimes when i get in and start the van i can hear the blend door/s being activated and i have not touched the controls. any thoughts?