Rewiring Thermostat to Furnace

Currently, the wiring from our furnace to our thermostat only has two wires, red and white. These two wires let our heat and fan to be on or both to be off. I want to add a third wire so that the heat and fan can be on, the fan only can be on or both are off. I got some new wire with three wires so that I can run a wire from G on the furnace to G on the thermostat. I hope that works! Below is a good website that lists the colors of wires and what they do. We don't have AC so that's less wiring for me!

I'm still looking for a good video about how to pull the new wire using the old wire.

http://www.dr-fix-it.com/ttt/10005.html

Terminal Designation	Wire Color	Function Description
Rh	Red	24 Volt Hot for Heating
Rc	Red	24 Volt Hot for Cooling
Y1	Yellow	First Stage Cooling
Y2	Blue	Second Stage Cooling
G	Green Grey *	Energizes Indoor Fan
W1	White	Energizes First Stage Heat
W2	Black	Energizes Second Stage Heat
O	Orange	Heat Pump Reversing Valve Energized In Cooling
B	Brown	Heat Pump Reversing Valve Energized In Heating
C	Brown**	24 Volt Neutral (Common) leg