I HATE map light switches, because they are just a "box" with wires, that is, Ma don' show the internal circuitry, and "I don't have one." Map switches use the switch MOUNT GROUND as part of the circuit so that's a problem
Here, look at the factory manual and see if that gives you a different perspective
There are several pages in the '69 manual that show bits and pieces of this. You have to diddle the page numbers because what your viewer shows is not what's printed on the pages