There should be a little button you can press next to the front cabin lights up on your upfitter overhead panel. I can't recall if its the left or right cabin light but they both have buttons near them. One is to keep the cabin lights off with door open and the other turns them all on at once IIRC.
Yeah it's kind of a weird setup. I'm not even used to it either.
One button on either side turns on the "map" light for that side.
Then the second button on each side does something different. One turns on all the dome lights, and the other one turns on and off the "with door" option I think.