Abstract: A bracket assembly for mounting a reed switch and associated magnet on an overhead opening door includes first and second interlocking pieces, both of which are stamped from sheet metal that is, preferably, non-ferromagnetic. Each of the pieces incorporates an opening sized to slidably receive a locking door bolt fabricated from a ferromagnetic material such as mild or hardened steel. For a currently preferred embodiment of the invention, both pieces of the bracket assembly are stamped from sheet aluminum. Both the reed switch and its associated magnet mount may mount on either piece, so long as they are on opposite sides of the opening. The assembly incorporates an opening that is sized to receive a slidable, locking bolt fabricated from a ferromagnetic material such as mild or hardened steel. When the bolt is withdrawn from the opening, the reed switch is activated, thereby generating a signal which can be input to a security system.