Trying to install a nest doorbell but need to change the transformer. I believe I found it here but it is attached to a switch next to the furnace. When I unhooked the wires the doorbell stopped working so I believe this is it. Would like a second opinion?
That is definitely what you're looking for. To be safe,trace the wires as far as you can to make sure they're not connected to anything else too. That's a strange location for one, mounted on a box to a furnace. Determine if the switch controls the transformer, that would be strange too. Make sure it's not feeding your thermostat.