I have an old gas furnace without a circuit board. Just a 4064 fan limit control, 24v transformer, gas burner control and fan. I wired a new wifi thermostat in. It works great. I would like to be able to use the fan only control of the thermostat. Can I do this? Where would I connect the G wire? I was thinking I could remove the jumper in the 4064 limit controller. But if I use low voltage on the limit side will it still only allow the fan to run by temperature? There is a fan/auto switch on the 4064 that works.