My fan for my heat and air in my 99 mercury mystique is working but I have no heat. I believe it might be that the heater core is clogged, but I can't find its location. I can't afford to replace the core, so I was wondering if was possible to flush it?

There is a switch on the control console that activates the heater door control. The door control is located behind the glove box. (You have to remove the glove box to get to it) If the switch on the console is bad, or the door control is bad, the door may not be opening to allow the blower to blow through the heater core and into the cab. I would think that if the core were plugged or coolant wasn't allowed through it, it would cause the car to overheat. its called a blend door it turns different ways door can stick causeing no heat