Abstract: A protective cover for a standard multiple-pin electrical connector receptacle of the type used to connect a trailer and a prime mover vehicle, the receptacle having a generally cylindrical body having at least one longitudinally extending orientation key protruding outwardly from the cylindrical body and a generally flat end having multiple electrical connecting elements recessed therein and an additional terminal protruding therefrom. The cover is comprised of a cup-shaped housing having an open end and a closed end and a cylindrical wall therebetween, the cylindrical wall having an inner surface and an outer surface, the diameters of the inner surface of the cylindrical wall and the cylindrical body being so related so that when assembled a friction fit exists therebetween to provide the principal means for retaining the cover in assembled relation to the receptacle.