When I turn my heat on, its not blowing anything but cold air.
No Heat in Truck on 1998 Ford Explorer
the heat switch is bad in dash
There is a temperature blend door actuator in the dash that may be set to cold and stuck there. However, before guessing at that, make sure the engine is getting hot enough. Check the inlet and outlet heater core hoses to see if they are both piping hot (careful!). If one or both are cool, you could have an engine temperature issue.