A/C problem, sounds like mixer valve

[egloskerry]

98 GP GT w/ climate control. I have had this problem for about a year. The air works fine if it is set to defrost or floor, but if I have it set to top vents, I barely have any air coming out of those vents, and most of it comes out of the floor vents. This problem only seems to happen in hot weather. I am guessing the mixing valve is binding. Any feedback?

[egloskerry]

Bump.

[egloskerry]

Still waiting.

[minichopper6hp]

is it the electronic? i have the same problem when i set it to the a/c. For extended periods of time, it works fine but eventually it goes to the floor and stops blowing out the top vents. I have to shut off the a/c and let it cool down before it will work right again. I have replaced the relay block but i dont know if that was the problem, or if the one i got was good or not.

[egloskerry]

So for anyone who finds this, the problem is the vacuum control valve solenoid. Part # is 15-72182. It's the small grey box attached to the blower motor, where all the vac lines go.