Car wiring diagrams: Focus Towbar Wiring Diagram, wiring diagram, wire wiring harness, schematic circuit diagram, wiring diagran, wireing diagram, wirring diagram, wiring daigram, wiring diagrams. Trailer Wiring Harness. Make installing your trailer wiring harness as easy as possible with a custom fit wiring harness. Make installing a trailer wiring harness on your Ford Focus as easy as possible with a custom fit wiring harness from Draw Tite, Curt, Pollak, Tow Ready, Bosal . wiring up the electrics on my girlfriends towbar to an mk focus. has it before ?? maybe got some type of wiring diagram. the instructions i .The towbar socket wiring is sorted, but I m struggling to find explicit wiring for which reason a photo or wiring diagram reference would prove .