Ford Repair: 1997 Taurus AC Issue, taurus gl, three knobs

Question
Shaun - I have a "U" VIN 1997 Taurus GL 3.0. I'm having an interesting issue with my AC at the moment. What happens is that I have an intermittent problem where the air sometimes blows at the outside temperature. Often, I'll start up the car, and everything works fine (5 minute trip, or 40 mile trips) from start to finish. Sometimes I'll start up and the air blows at ambient temp, then the cold kicks on a minute later, or 5 minutes later. Other times I'll be driving and everything's okay then it'll go warm, then back to cold , then back again a couple of times until at some point it stays cold.

All this to say, the I don't see any ice accumulations or anything, and when it blows cold, it's as cold as it normally is. There's also no discernable patters to the this issue: Doens't seem dependent on temperature, or if I've driven previously. Any ideas? Thanks so much!!

Answer
Hello Randy,
    I see many temperature blend problems on later model Ford vehicles like yours. Most of the time it is caused by a faulty Blend Door Actuator, which on the Taurus/Sable model, is accessible by removing the radio/climate control panel. It takes an inexpensive set of special tools and a little technique to remove the panel. Assuming that it doesn't have automatic temp. control and just has the three knobs, it is possible that the actual rheostat behind the knob is faulty, but not as likely as the actuator. The actuator is a plastic rectangular box about 4" across, usually held on by 3 or 4 5/16" screws. Some models you have to remove the entire instrument panel, but not on a Taurus.
    Also verify that the air is not intermittently being routed out of the defrost vents, which is a sign of a leaky vacuum hose,check valve,or storage reservoir for the other doors underneath the dash. Some parts still work off of vacuum, so as engine vacuum decreases with throttle movement, vacuum is stored in a plastic tank(usually under the plastic fenderwell). Vacuum is supplied to this reservoir by hose and check valve, and if that valve does not hold, the vacuum supply will drop off also, causing the vents to change. Just some more info. to consider.
    I hope this information helps you, and feel free to follow up anytime. Good luck.   Shaun.