2004 Explorer. A/C defrost always on.

[thetexasairman]

My '04 Explorer a/c works fine with one small exception. I have manual controls and everything works normal, except that no matter what setting I'm on, the defrost blows continuously. And that leaves me with frost on the windshield constantly except in the warmer parts of the day. Its been doing it for about three months now. How do I get the defrost to only come on in the defrost position? I tried replacing the control switch (third control on the right - next to passenger side of the car), but it didn't make any difference. If I turn the control off, everything stops as normal, but other than that it blows out the defrost continually. I repaired the blend door which had fallen off, so it stays in place, so I know that's not the problem. What do I need to do to fix this?

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the A/C & heater section. Check the hard plastic vacuum tubing for cracks. They usually break at the point where the rubber adapter connects to the servo piston. There is a vacuum reserve tank that could leak if it has a crack. Check that as well.

 

[thetexasairman]

Thank you.

TO: BROOKLYN BAY: Thanks for moving it. I had just noticed I put it in the wrong year model, as well. I don't know how the system normally works, but I'd think that the vacuum lines would be okay since the other controls appear to work. If I put it on the different positions each one works as normal, except the defrost is on in any position. I'll still check the vac lines, but I'm thinking it is in one of the controls. Since there are two servos for the defrost, I can't see both of them being out at the same time, so the vac is suspect.