I took my bed off about amonth ago. I ran stacks by the cab, like the nice blue diesel under the "frenched stacks" forum. I had two trailer lights mounted to the frame for tail lights. Everything worked fine, until yesterday when I put the bed back on. Hooked up the lights, I have stop, turn and hazard lights and reverse, but no parking or night time marker lights in the rear, or license plate lights. Front parking lights work. I unhooked the light sockets at the first spilt going away from the tail lights. I get juice to everything except the running, parking light terminal. I have checked all fuses, none are blown. I am clueless on how test a relay if that could be an issue. Could this be a bed not grounded issue, a bad wire somewhere in the miles of wires, or a faulty headlight switch in the cab. truck is a 2001 ram 1500 4dr ext cab 4x4 SLT, 5.2L v8. Google search turned up several things. bad ipm(engine fuse panel) bad hazard fuse in engine fuse panel(doesn't appear blown, its the square one with a clear removable top section 20amp rating), bad headlight switch, break in a wire / shorting out somewhere, junction box under bed for rear lighting and lastly bed not being grounded and circuit not being completed. Cant remember if bed was grounded when I took it off. Any suggestions helps.