Hi On your veh the in car temp sensor can control your recirculated air flap ,after pushing the switch on it can take up to five minutes if the temp out side is cold ,if a/c is om and its hot the system will go to 100% recirculated air for up to 30 minutes and then go to 80 %,as stated in prior post you will not haer a change ,yet you might feel the cabin cool off faster and maintain cooler air when hot outside.joeym