wish to wire in a switch for my blower

[beckrc]

I just moved into a used mobile home. The original furnace only had on and off, so there are only two wires in the walls. Previous owner had installed a new furnace with 5 wires, and connected the red and white to the wires in the walls of the home.
I realize the green is for the blower, and I wish to wire in a switch to control the blower so I can turn it on, rather than have it stuck on "auto". This would allow me to distrubute the heat from our wood stove without having to rerun new wiring. We have heat only, no AC.
Is this possible? Can you describe the procedure and how to do the jumpers and switch connection?

[Hube]

Without any info as to make, type of unit, it would be foolish to try and advise from here.These 2 wires ,are they from the THERM? Some mobile units have a "BOARD" which can be ruined because of wire errors. And expensive. Obtain a manual on this unit and then you will see if you can run the fan separately from the heat mode. Hube