I got a 1994 Civic LX Sedan and the heating no long works. I have narrowed the reason down to the slide thing that mixes the hot and cold air (it goes blue then red). The fan speed works fine but the mixer doesn't seem to work. It slides real easy, then sticks in the middle and it take a quite of bit of force to get it over to the blue side. Any suggestions on how to fix this? Also, anyone know how to take the center consol apart so i can get a better look?

 

I've got some pics, got to find them though. I had the same problem, but made the unfortunate mistake of forcing it a little too much one day. The piece of plastic that retains the cable so that the line that runs throught the cable isn't holding. It's like a bicycle brake cable. the cable guides the wire as it slides through it. you need to remove your stereo to get to it. I was going to replace mine, but it cost about 140 from a junk yard and 240 from the factory. you havet o replace the whole heater controler assembly. It's called the air mix control cable. I'll post those pics when i find it.