Furnace making clicking sound when it is already running

I have also heard the exact same thing and it does come from near or at the AC unit in the ceiling. I have a 2014 FR3 and I concluded it is something new in the electronics. I have heard it when the furnace is running and it occurs just before the thermostat cuts off. It is not heat expansion and is a regular clicking just like you would hear from an igniter for a gas stove or grill. ON new models the AC unit blower and heating are tied together in some way.