Both of the trucks that I use to pull trailers came wired from the factory with the 4-pin or square style trailer light plugs. Whenever I borrow a friends trailer from time to time I have to run with no lights since his trailer is set up with the 7-pin round plug. Does anyone make a converter to mate my 4-pin square to a 7-pin flat or blade style plug? I have searched every parts store in town but to no avail. Thanks for any and all help.