While working inside the son's truck, sometimes we will have the doors open for hours at a time.
First, I just removed the dome-light bulb; but, this involves a screw-driver and a chance of messing up the bulb holder.
I thought about dis-abling the door triggers; but, I came up with a better solution.
I cut the HOT wire at the light and spliced a short lead-wire to each cut end.
I connected these leads to a SPST toggle-switch.
I bored a suitable hole in the cab roof, a couple of inches left of the dome-light, and installed the toggle.
Now, with a flip of the switch, I can kill the dome-light, and not worry about it running down the batteries.
This was sort of a quickie job; but, when time allows, plans are to design/add a circuit that will operate the dome-light, and other interior lights, independent of the headlight switch.