harness separate. like $15. Buy the harness it is well worth the money. The harness coming off the back of the timer plugs into this adapting harness and then into the "ignition" harness. My recommendation is to take off the cover around the steering column (like 6 screws from underneath). Then follow the 5 wires coming directly off of the ignition solenoid. I would recommend also taking off the under panel of the interior that is right above where your knees would be and then the tube for the vent in the door panel which runs underneath. then look around the steering column and the harness should be there. It is pretty easy just a pain on the back underneath there. good luck