Yes it could be the blend door actuator or the blend door broken inside the heater box.
The problem might not be the switch, it might be the heating core that is in the dash. It is essentially a radiator that is under the dash that.
Hi, have a Escort LX Wagon with miles. I live in NH and it is starting to get cold up here. On way Home tonight from work at 11 pm.
My heater is not blowing out hot air when the car is sitting still or idling a light you can smell exhaust fumes.
no heat means no hot water making it to the heater core many fords have a valve that controls hot water flow to the heater core.. it could be stuck or the vacum.