The 55.2 wiring diagram only shows the headlight switch providing ground for the dome light, so that would be easy to intercept that wire under the dash for grounding door switches. I assume jmoore's 57 is the same.
But the AD trucks (including Patharr's 1952) only have a single hot wire going to the dome light, switched by the onboard switch at the light. So additional wires would have to be run to the dome light, OR the onboard switch left on and isolated 2 terminal door switches wired into the hot feed to the dome light for door switches to work. That would result in ONLY the door switches turning the dome light on, and not the onboard switch.
