Thread the three wires into the bedside curl and all the way to the splicing points on your truck wiring harness. Make permanent splices to the appropriate wires and seal them with heat-shrink tubing (or the SpliSeal system) to prevent corrosion. Once the wires are connected the next step is to install the cap inside the bedrail curl. All Mar-K hole caps have an O-ring that will aid in making a good tight fit. Due to the many model years of usage and the variations from one truck to the next, the parts may not fit perfectly, especially if your bedside has had minor damage-so you may have to file the aluminum cap housing slightly or reshape the curl opening if there is a tight spot. Be sure to test the lights for proper operation. When you are ready to permanently install them, apply some epoxy or other durable adhesive to the O-ring area before inserting them into the bedside curl. This will help prevent them from falling out or being easily stolen.