I was driving my hatch a couple months ago and while I had the A/C on I switched it over to mix. Now regardless of where I put the selector the air circulates like it is on mix, anyone have an idea where to start looking?
I just fixed mine a few days ago. First and easiest place to check is the vacuum hose in the engine compartment. It runs from the passenger side right beside the firewall, there is a small three way connector with one vacuum hose running from this to the driver side where it connects to the vacuum block ( it is marked a/c, b/r, etc.). Make sure this hose is connected to the vacuum black and there are no holes in the line. This is the most common point that it leaks. Mine ended up being a vacuum hose that fell off in behind the the radio right behind the HVAC controls. Plugged it back in, and works fine now. If you recently installed a new stereo I would start here as you may have knocked off a hose.
i would check the knob.the are prone to breaking so even if you turn the knob its not changing the setting.take the knob off and look behind it you should see that the knob is the same shape as the shaft it is supposed to turn sometimes the get old and crack and cant spin the shaft.
I had the same thing happen. The vaccuum modulator was shot. I'm pretty sure there are 2. You can find one to the right of your radio. Try and work the plunger up and down and see if it sticks.
Mines a 91 so I doubt its the knob, cause I wouldn't be able to turn the A/C on at all if the knob was busted. I kinda figured it was vacuum related. I'll bust out the pump and see what I can find. Thanks for the ideas guys.