Rear Marker Light issue on 05 Land Yacht 30SL

[kenajen]

I was trouble shooting a single red marker light over the rear window and found a corroded bulb and socket. I ordered a new light fixture from NAPA and then removed the old unit. The old one has 2 black wires, I guess that is due to the fiberglass body having no ground path. The new unit has only one wire and I guess that the fixture and screws are part of the ground path.
Now the problem: When testing the old socket with a volt/ohm meter I lost all of the red lights above the rear window and the three driving lights on the drivers side only. I checked the fuse and it is OK, and when removed all markers (yellow & red) and all tail lights go out, and come back when the fuse is replaced all but the ones mentioned earlier.

In my limited knowledge I would say that I blew a fuse or opened the circuit in the path of the lights that are not working. I have no DC at the wiring that I was working on at the defective socket. Could there be another fuse I'm missing? It reminds me of a Xmas light string.
Any help would be much appreciated!
Ken

[kenajen]

I found the gremlin!
After checking every bulb and socket of the clearance/marker lights that went out I dug into all manuals relating to the coach and chassis. What I found was the marker/clearance lights are on the left or right tail light fuse. This panel is under the hood. The marker/clearance light fuse is under the dash on the drivers side. Both fuses when pulled kill the markers and the tail lights. The fuse was a 5A mini under the hood. WOW did that drive me crazy!