Abstract: A method of attaching a flat annular contact plate of a horn ring assembly to a flat annular flange of plastic substrate such as a turn signal canceling cam includes the steps of forming deformable tabs on the contact plate perpendicular to the plane thereof, forming slots in the substrate adjacent an inner edge if the annular flange, forming integral plastic shrouds with pockets therein adjacent the slots and perpendicular to the plane of the flange, seating the contact plate agaianst the flange with the deformable tabs projecting through the slots into the pockets on the shrouds, and bending the tabs against the flange to clamp the contact plate to the flange. The pockets hold the shrouds over the bent tabs and prevent spurious electrical contact with the tabs.