Craig-
I understand the frustration... look at enough lights on enough Web sites and your eyes start to glaze over.
Here are the questions I use to find replacements.
1) What are the manufacturer and model of the original light?
Some lights have those stamped on the lens.
Sometimes the coach manufacturer will tell you.
2) What is the distance between centers?
3) What are the length and width of the light?
4) Does the light also function as a turn signal?
5) What kind of wiring connectors are used?
6) Does it require a mounting gasket or grommet?
The answer to question 1 often is all that's needed, unless the light manufacturer does not have drawings or documentation.
The original manufacturer of your light probably has a direct LED replacement. If not, scan the
Peterson Manufacturing,
Grote and
Truck-Lite sites. They (and others) supply to the online retailers, like
Iowa80,
SuperbrightLEDs and
etrailer.
Mark