Furnace

[Busdriver]

? Have a clicking sound in my A C that happens just before ny furnace kicks on, they both operate from the same thermostat maybe be a feedback from the thermostat

[enblethen]

It should click only once to energize and again to drop out.

[doxiemom11]

Ours clicks - it's the relay located in the A/C that will turn the furnace on.

[enblethen]

Make and model of thermostat?

[Busdriver]

Several clicks

[enblethen]

A single click is normal, more then one is not!

[Flute_Man]

Do you have one zone or two?

[DrewE]

One single click? That's just the relay in the air conditioner control board that activates the furnace, and expected. It's a common setup in RVs, though not universal.

The thermostat connects to the AC control box, which in turn switches the furnace on or off (well, activates or deactivates its control line).

[enblethen]

Possible thatn the thermostat is failing. Relay in AC control board is not getting good signal from thermostat.
Make and model of thermostat, furnace and AC?