You'll have to figure out where your source of power originates at, either in the fan box or the light switch. A lot of times 14/3 wire is run from the light/fan box to the switch box, but one wire carries power to the switch box and the other returns power to the ceiling box. This is usually done to power an outlet on the wall near the switch box, and in this setup you cannot run two separate switches for a fan setup with out running additional wire.
Figure out where the power comes in at (should be a 2 conductor plus ground in one of the boxes. You will have to disconnect some wires to determine which is the hot one. Give us a description of the wires and how they are connected in the switch box for the porch light, switch box for the fan, and the fan box. Pictures would help to describe this in better detail.
Figure out where the power comes in at (should be a 2 conductor plus ground in one of the boxes. You will have to disconnect some wires to determine which is the hot one. Give us a description of the wires and how they are connected in the switch box for the porch light, switch box for the fan, and the fan box. Pictures would help to describe this in better detail.
