96 ZJ with factory IV tow package; need to add a brake controller.

I found the blue brake wire behind/above the driver's kick panel, but read a post saying the other wires should be there too. There's a free small black connecter about 1/4 inch square that has a red with light blue tracer wire and a white with thin purple tracer wire coming in and a blanking plug in the end; would these be anything to do with the brake controller wiring?