The answer, as shown by the schematic, is that the instrument cluster microprocessor turns on the automatic lights and there are manual switches, too. BK/LtBlu is the wire to look for in the ceiling.
It's such a good thing that Ford ran this through a microprocessor because dome lights never worked right without a microprocessor. (Yes, they did). You might find the problem in the Battery Saver relay, only a Sawzall away, in the dash above the driver's left knee. Fuse 17, same place. Then the instrument cluster microprocessor is supposed to respond to door switches, so all the door switches might be bad or the microprocessor. Only a few hundred dollars for a Dealership to fix that high tech light switch. Then, you could find, as on my Explorer, that the BK/LtBlu wire is NOT connected to all the dome lights. In my car, the front dome light stays on all the time and the rear lights work as they were designed to work.
There it is, laid out for you. Check what you can, pay for what you can, and just give up if you don't want to tear out everything from the door liners to the dashboard to the headliner.
Personally, I carry a tiny LED flashlight so I can see inside the car at night.
