Check the voltage on the two wires. Are there any others inside that box? If not, I suspect the black in the switch box is the source (hot) and the red is the load.

First off, is there any white at the switch box? They may have used two hots (one for the fan and one for the light, if they "prewired for a fan/light combo." If there is no white, what you probably have is a switch loop where the power runs to the fan and then only the hot comes down to be switched by the switch.

Note that if the thing wasn't preplanned for a fan, the box is most likely NOT STRONG ENOUGH to safely and legally support the fan and will need to be replaced.

"secondly i tried to hook it up with my fan and the combos worked, just the switch wouldnt turn off the fan." Combos?

1. Post a drawing of the cable(s) that enter the wall box and the colors of the wires they contain. Indicate which cable runs from the wall box to the ceiling box. Show how the old switch was wired.
2. Post a drawing of the cable(s) that enter the ceiling box and the colors of the wires they contain. Indicate which cable runs from the ceiling box to the wall box. Show how the old light was wired.

Are you sure that the fan can be controlled by wall switches? Some fans require constant power and the fans and lights are controlled solely by a remote control.

What fans require constant power? I have installed three different brands of remotely-controlled fans, all on circuits with on/off switches on the wall. Yes, the remote won't turn them on if the wall switch is off, but once you turn them and set the functions (direction, speed, brightness of light) with the remote, I can turn them off from the wall switch and these settings are remembered when I turn them back on.

The point was to distinguish between fans that are controlled by fan/light wall switch like this Lutron MACL-LFQH-WH from fans that are controlled by a remote and require "constant power" for the remote to work. I made the mistake of wiring up the Lutron switch for a fan to be installed later and then, oops!, found a fan I really liked that could be controlled only by its remote.

Yes, I find that frustrating also. My preferred way to wire light/fans is to have two wall on-off switches to turn on or off the fan and light, but to control them with the remote.

Not to drag out the thread, but the Monte Carlo Clarity II and Fanimation Upright fans -- and presumably other fans by these manufacturers -- support only one pair of wires. One can't have separate wall switches for fan and lights.

I have a cute little fan controller that mounts in a box from MikaAir (I think). It doesn't actually switch the fan directly. It's radio controlled. I was sitting there with the fan running and holding the fan controller in my hand. I'm thinking, hey I got to pull this switch and put this in. It quickly became apparent that I could push the buttons on the disconnected fan controller in my hand and control the fan (it has a battery inside it).

Monte Carlo fans includes this remote control that can either be enclosed in a case (provided), or attached to an electrical box behind a Decora wall plate. The remote doesn't attach to any wires inside the electrical box -- it is battery operated -- but looks and acts just like a wall fan/light control. Clever...and you can't lose the remote!