If you don't have the tow package which I am assuming you don't because you need a harness then you will have to splice into them. Will be easy enough to do though, you shouldn't have to cut wires. Make sure the connectors are waterproof, ie. have silicon goop on them, so you don't have electrical problems down the line.
'03 TJ Sport
/ D30/Ford9 / 35x12.5x15 KM2 / D window black steel 15x8 wheels / 3" custom long arm lift / SYE & 1350 DS / JKS BL / 1" MML / Smittybilt's front bumper, Tube fenders, Rocker guards, and rear bumper / High Rock Tire Carrier