My goal is to add support for my furnace fan on my Nest Thermostat.

Looking at the furnace the board has many terminals, but not all are connected. Can I connect the G terminal to the G terminal on my thermostat?

My gut says, yes, but is there anything else I should check before doing this?

More information about the current configuration as requested by Jphi1618:

  • The furnace has wires connected to R, C, W1, W2, Y1, Y2 with open terminals for E1, E2, HUM, G
  • The Nest Thermostat I have is connected to R, W1, W2, Y1 with a jumper on Y1/Y2 at the furnace
  • 1
    It's a little unclear what you are asking. It's obviously not going to anything with just one wire connected. What thermostat do you have now? What other wires are connected? Also, the G terminal on a thermostat usually makes the blower run rather than controlling cool or heat.
    – JPhi1618
    Oct 20, 2021 at 20:43

1 Answer 1


This should work

As long as your spare wire is continuous through the thermostat cable, you should be good to go with connecting G on your furnace to G on your thermostat so that you can manually command the furnace's blower to run.

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