So far I have two circuits shorted on my 82 Excella. One was for the porch and flood lites and also fed the lites over the stove and a lite in front of the air conditioner. It was a #12 awg color orange. I was able to pick up power for the porch and flood from the switch that feed the vent lite in the couch area. All three switches were located on wall by the door. I picked up power for the lites over the stove from the stove vent motor feed. The other short was the tail and marker lites all of these must be on the same circuit. I got the tail lites going by useing the wire for the backup lites and moving it to the tail lite position in the fuse panel. As stated many times it is not very likely that you can fish in a wire because of cross members and insalation. I wish Airstream would pull all the wires in conduit! I have replaced all the marker lites and tail lite holders so the shorts must be in the wireing runs somewhere. ( By the way NAPA has rebulid parts for your socket lites new contacts and springs, they just drop in after you remove the old ones).