Return Air Ductwork For Sale Is There Suppose To Be A Damper On The Return Ducts Or Maybe The Unit Itself For A Home HVAC System?

Is there suppose to be a damper on the return ducts or maybe the unit itself for a home HVAC system? - return air ductwork for sale

Sensation of cold air through the register, if the fan is not on.It is a two-story house, and I checked the wires and no breakage or leakage. I looked into the canal and there is nothing on the back of the opening speech of unity. Only a square opening something else. This is a butterfly that is found (at best) if we need to be made, can be found in the canals? (simple)