An electronic control unit for a motor of an electric fan, has a support casing including a metal body adapted to act as a heat dissipator, a shell of an electrically insulating material coupled with the metal body, and a circuit board, mounted in contact with the dissipator body. The circuit board has a conductive connection member in the form of a flexible metal blade, electrically connected to the dissipator body, to provide an earth connection for the circuit board. The blade has a portion that projects beyond the edge of the board. The insulating shell has an internal formation which, upon coupling the shell with the dissipator body, interacts with the projecting portion of the blade, deforming it so as to bring it and thereafter maintain it in contact with the dissipator body in a resiliently loaded manner.