not to long ago I had the heater core replace man did it blow hot air then one day it was blowing cold air so I took the glove box out then I see the cable came off and the pin where it goes to the blend door so I move the blend door all the way to the left which is for heat its blowing warm air but not as hot as it use to and also for a while their outside air coming in on the passenger side where the fan box is but I think its just the flap that does outside to inside air mix the foam wore off this has been like this even when it was blowing hot air.