All our radio shack had was this part number, but it had 3 prongs, not 5. My stepdad used to be a wiring king and he says that the 3 prong won't work... that it will blow the finals out of the head unit.... so I need help finding a part that will work. Thanks. I tore everything out today and had my homemade harness made, but it looks like it isn't gonna work?