The fact that the license had a single wire is important. When you call Airstream for a routing diagram. If they do not discribe that light as the end of a series including all of the tail lights or as a seperate routing from another fixture, and say which fixture, they have blown you smoke.
Unfortunately Jackson Center all to often blows smoke when ask a hard question. When I was looking for parts for my roof vents I have had then claim they never used the parallel lift roof vents and that I had to have installed them.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles