Input mappers

[Nitsujy12345]

A question for those who know more about this than I do.

I’m using the DTG GP40-2 pack as a base for a personal-use project, and would like to be able to turn the ditch lights on as a key bind. This feels like something that SHOULD be simple, but I don’t have a clue how key binds work when they aren’t already in place. Anyone have an idea on how to make a cab switch have a key bind?