Hello all, I just fixed my slider on my non a/c heater control for my 68 Firebird. I am not sure of the purpose of putting a cable onto the blower low/medium/high slider. I understand the following for the other 2 selectors and they work: I can hear and feel the air doors sliding open/shut in the air box for the heat/de-ice slider, and the hot/cold slider. My slider for the blower speed, low, med, high works; the blower speed changed without that third cable being hooked up. This third cable is very tight, it will snap off the stud on the slider if I hook it up. I plan to leave it off unless someone tells me a good reason to hook it up. The service manual picture is useless, it is very vague. This is kind of hard to explain, so any ideas/insight would be greatly appreciated. Thanks, Jeff

"it will snap off the stud on the slider if I hook it up"

You can adjust where the cable is clamped therefor adjusting the throw on the back of the slider. Takes a little playing around but if you have stock parts you should get it to work without any hangups.

Doug- Thanks for replying. Do you know what this cable does exactly? I don't understand the need for a cable to move with the low, med, high blower setting? Thanks, Jeff

That cable opens the "air" door. Otherwise the fan has no intake. To get at the lever it's best to pull the glove box out. Even with it in you can reach up and over the top behind the heater control mounting location and feel the lever.
There is a special clip for this lever, different from the other two that holds the cable in place. If the cable is binding, remove it and soak it in WD40 while moving it through the range.

I would say the top lever is obviously for the fan, the next lever is to control the mix of hot air to fresh cold air to achieve your desired temp, and the last lever switches from heater outlet to defrost outlet. I bought new cables from firebirdcentral.com and they did not match the origional lengths at all. They were much longer. The fan and heater/defrost work great, but the cold/hot control seems to be backwards. It is baffeling because I know all cables come out of the control on the same side, and I know that the cold/hot control behind the glove box has a mount to secure the cable on the left side, and attach to the shaft connected to the flapper. There is another shaft at this location that would let the lever operate in the opposite direction, but there is no way to secure the cable.