A/C and vented air being heated

2003 Taurus is heating the air when the vent or A/C is on. When outside air is 70 degrees, the vented air is heated to 95+ degrees. A/C works, but struggles to cool the heated air. I removed the plastic cover under the dash to look at the vent operation. The blend door and actuator works fine as you adjust the temp dial. I think the problem could be the valve allowing coolant through the heater core. Anyone experience this problem? Any ideas how to get to the valve (if it has one) and how to test it?
I have found TSBs from Ford talking about HVAC problems, but no details or corrective actions.
Thanks.

I own 2 Taurus' that have had the same exact problem. The problem is the climate control module. I had the one in my 2002 Taurus replaced since it was under warranty, but I do the following to reset it in my 2000 Taurus:

Open the glovebox and press the spring tabs that hold it in place and allow it to swing downward. This will give you access to the area behind the glovebox. Look into the area just behind the glovebox to the lfet side behind the radio area, and you will notice a small electronic module (about the size of a cigarette pack). This is the Climate control module. You will see some vaccum lines and electrical lines connected. I reset mine by removing both sets of lines and then proceed to crank the car and cycle the air conditioner a number of times. It may take 2 or 3 tries before it finally resests, but don't give up, it will eventually reset and cold air will again blow through the vents. You will hear the blend door flip over when it finally takes.

Ocasionally it sticks again, usually when there is a cool morning during the warmer months. I have also found that leaving the air set at 60 degrees all the time and adjusting the fan stops it from occurring as much as using the auto setting.

Or if you're not as stubborn as I am, you can just go buy a new one and replace it.

Hope this helps.