So my 08 Ranger has been giving me problems lately:
First the temperature control stopped working such that it would only blow hot air. I tracked the problem down to a non-functioning air blend door motor which I sucessfully replaced.
Now the new problem that just started is that I only have either heat or A/C from the vents. To clarify, the blower fan selector switch still properly controls which vents the air comes out of but all of the settings result in air-conditioned air (unless I turn the heat up but even then it's probably just heating air-conditioned air).