Heater stuck on

[deliriousga]

We've had a problem over the past few years where if the outside temp was around freezing the heater would not come on. I could hear the flap under the passenger side dash trying to flip to heat, but it wouldn't do it until the car warmed up if at all.

Now it has suddenly stuck in the heat position. We can turn off the system so we don't boil, but it won't flip to A/C and the Georgia summer is on its way. I've never tried to diagnose this stuff on an electric climate control system so I don't even know where to start. Any ideas would be wonderful.

Thanks!