wiring a trailer harness

Get a test light from the auto parts store, it has a point on one end to pierce the wires and a led in the handle plus a grounding latch on the end of the wire that comes out of the handle. connect the ground wire and turn on the turnsignals, start piercing the wires till you find the one that makes the led flash on your test light do this till yu have found all the wires that work the test light properly. The trailer hookup should have a wiring diagram and instruction on witch wire does what for the trailer lighting. Hope this helps cdhaze@msn.com