This is a minor thing, but in the mornings I noticed my temperature control dial will not stay on the coldest setting. When I try to turn it all the way cold (counterclockwise), it springs back towards hot (clockwise). After I drive a ways, it will stay on the coldest position.

Let me guess....this is some automatic Toyota self protection feature to prevent the A/C from getting a thermal shock? :o

I have about the same problem. Mine comes when I get in the truck on a hot day (over 90º). The dial won't go to full cool position for several miles (or until the cab cools a few degrees). Anyone know the reason for this?

mine never stays. period. it always springs back to about the 9 o'clock position. I can hear a reduced air flow between the full cold and 9 o'clock positions, as well as the reduction in cool air temp. I have a little piece of rubber I jam between the knob and the bezel to keep it at full cold. (if you push the knob a dime will fit in the gap too...;) )
glad mine isn't the only one that does this.

I have the same problem.

My solution so far is to turn the fan speed off and then rotate the temperature setting all the way to cold and turn the fan speed back on. It has worked every time so far. Hope this might help someone.

you have cable and/or an air door binding. yspert

All the temperature dial does is modulate the heaters water control valve on the center firewall under the hood. I think Toyota may have set the control dial to a safe position on the cold end. This was because the cable adjustment clip by the control valve doesn't always grip tight and owners were complaining that their a/c outlet temperatures were getting warmer. If you're getting cold air leave it alone. If you think it's too warm in a/c mode check the clip and the valve lever travel and readjust as necessary. There are earlier posts regarding this.

Larry