I was able to fish new wire to the five running/marker lights across the front of our Safari. I used a Dremel tool to enlarge the hole behind each light just enough to get a wire nut through it (dime to nickel size). I was very careful to keep the hole well within the footprint of the light assembly.
When possible, I pulled the new wire through by attaching it to the old wire. Where the old wire had failed completely (and it had in places) I used an electrician's fish tape, 1/16" welding rod with a hook bent into the end, and a lot of prayer and persistence.
I did the front lights only, and did not have to fool with tail lights, etc.
After the wires were in, I sealed the holes with sticky aluminum tape (like they really use on air conditioning ducts, not the stuff we call duct tape). The new LED lights I installed required a hole in another location. I drilled these where required and used a plastic wall anchor as a grommet around the wire. It fits flush with the skin and protects the wire from the aluminum edge of the hole.
After the lights were installed, I used a generous bead of Parbond around the light base. So far, nothing has leaked. (Fingers still crossed.)
My thread on the subject is at http://www.airforums.com/forums/f447...lem-85885.html