Hi, the cabin air on my 02 Laredo is stuck on the windsheild defrost. The **** selector for the vents, defrost, floor, etc will turn the air on and off but will not move the actuators(I'm guessing) to another position. Does anyone have an idea of the what the problem is?? thanks

 

Check your vacuum line the runs into the firewall. If that is broken then only the default will work which is the defrost only. This is the exact problem and solution i experienced.

 

Also check where that line, and others attach to the manifold. They tend to crack with age, and that causes a vacuum leak which can cause your issue. Check their condition and replace if in doubt.