So i dont believe someone has posted this exact thread,if they did I'm sorry. But here is my issue, I have no taillights,or dash lights,nor do I have license plate lights. (But those run off the same wires as the tail lights if I'm not mistaken so that makes sense. I do have blinkers front and back,i have reverse light, and headlights. I've already replaced the headlight switch,all fuses are good, if I did it correctly I seem to have power to the bulb on the brown wire. I tore the dash apart and it has the 2 rows of bulbs,all are good. All this happened after I changed the bed,installed a new radio and brighter headlights. (I did unplug the new headlights and the stereo,it did not fix the problem.) I even went to the junk yard and pulled the back portion of the wiring harness to see if that would fix it,nope. I don't know were to go from here? Did I miss something? Any help is welcome. This is all on a 1990 f150 with a 5.0 v8, standard transmission.

 

I would double check all the body grounds (cab to engine, cab to frame, and bed to frame), disconnect, clean and reinstall

 

The bed to frame one would be the only one I've messed with,however I don't recall unhooking any ground wire from the bed when I took the old one off?

 

You might have pinched a section of the wiring when reinstalling the bed to frame, and I've pulled over 20 beds never seen a bed to frame ground cable.

 

Find your ground problem. Grind the rust away. You need a vom an circuit tester. You can then circuit continuity test. If your ground is fixed make sure corrosion isn't in the fuse box. Corrosion can get inside wires an eat them, the copper up so continuity of the circuit will be gone. This is a methodical search a cross of the list type diagnostic problem.

 

Do your front PARK LIGHTS work?

 

Yes,well to be honest I can't remember and I'm not home. Sorry,would it be a different issue if the do versus if they dont?

 

I don't see how I could have done this, all my wires are inside the frame rail,nothing runs on top were it could get pinched.

 

Grounds are good,when I bought the truck a yr ago I replaced the ground wires and sanded down the metal were they made contact. When I checked the fuses I pulled it from its mount to make sure it had no loose wires and saw no corrosion.

 

I would say so, beings they switch on together basically through the same feed. But understand, I am not implying that the light switch is bad.

Anyway if I was working on it, I would certainly wonder. There could be a clue there somehow.