'74 Dart, 225 /6, A904, Factory AC/Heat. The counterbalance wheel does not appear to be functioning. Marked it before I warmed up the car, drove it 40 miles, and the wheel has not rotated. I've attached pics of both sides. Is everything there? Is there a bi-metal spring that operates it with applied heat? Can the spring be replaced? If so, got a part number or where I can get it? It rotates easily and feels like it's opening and closing properly. I'd really like to get it functioning correctly. Any and all help is greatly appreciated!















