Funny you should ask, as I literally just got finished posting a thread about doing this in the General Halloween sub-forum. Here's the link:
http://www.halloweenforum.com/general-halloween/82136-f-x-constant-fog-mach-timer.html
Now, keep in mind that this is for a Lite F/X Constant Fog machine. If you aren't using this same exact fogger, you will need to figure out what wires the switch is wired to in your remote. Once you figure that out, you should be able to follow the same directions in that other thread to achieve your result.
-=coasterbp
http://www.halloweenforum.com/general-halloween/82136-f-x-constant-fog-mach-timer.html
Now, keep in mind that this is for a Lite F/X Constant Fog machine. If you aren't using this same exact fogger, you will need to figure out what wires the switch is wired to in your remote. Once you figure that out, you should be able to follow the same directions in that other thread to achieve your result.
-=coasterbp