thermostate wiring
 

I have a gas furnace "Trane 80", which was operated by an old round thermostat, and a two conductor thermostat wire.There was no switch to turn on "summer Fan" manually. I replaced the old thermostat with a "Garrison" programmable thermostat. If I want to have manual fan control, and wire for future Air Conditioning, how many conductors will I need to pull?

Depending on the model of Garrison thermostat you have, you will have to run a 5 wire thermostat cable.
P.S. - better to have asked this in an original post.

cnordstrom; Welcome to the site.

It always depend in the model becasue we have one thermostat available and there is no conductor need to pull.