Luvnprogress if you have the same Painless harnass I have you should have these wires zipped tied together going to the tail lights. Grn-Right turn, Ylw-left turn, Brw-tail lights, Orn-third brake light, Wht-License plate light. My harness did not have backup lights. But if you just have 2 wires to each tail light, hook up the turn signal wire to the brighter elememt in the bulb, and the tail light wire to the dimmer elememt. You then can run a wire out of you tail light wire to the licenes plate, and the side marker lights on the bed. Then put a ground wire on the lights and everything should work.

Let me get back to you on the heater.
