A/C vent will not switch to front to blow air?

The description sounds like the mode control actuator has stopped working. There is a test for it, and it uses the connections shown in the images. You basically unplug the electrical connection and use jumper wires to connect battery + to terminal 6 and the negative to terminal 7. Then you touch another wire connected to ground to touch the listed terminals to see if it moves properly. To access it you remove the trim panel from under the driver's side dash and then the air duct and above the duct is the actuator. Remove the screws and the electrical connector and remove the actuator. Then reverse the process to replace the actuator.