This is what the interior looks like lit up with a Euro rear dome light installed with high power LED bulbs in both front and rear.
This can be done with a Focus wagon rear dome light and harness, but I imported a harness from the UK that also has lamps mounted above the visors for the vanity mirrors.
I'll start with the rear lamp first, since that's what most people will probably want to install. My car has a moonroof, so the shape and location of the rear lamp may vary a bit for non-moonroof cars, but the procedure should generally be the same.
When you remove the headliner, this is what the top side looks like... notice the oval-shaped area towards the rear. This is where the rear lamp goes! Nice of Ford to give us a template.
When you buy or salvage a rear lamp, make sure you get the mounting ring, and don't mess with the tabs too much! It's just a stamped and bent piece of sheet metal, and those tabs will break if you bend them too many times. Locate the ring on the headliner and mark it with a sharpie, with the longest tab towards the rear:
Then using a sharp knife, simply cut the hole out. You want the trim ring to be tight to the headliner, so start small and then trim away the excess until the ring just fits, then bend the tabs down to secure it.
Pop the rear lamp in with the switch towards the rear, and that part is done!
The next step is the vanity lights if you have them. All they are is a molded plastic lens, metal mounting bracket and the bulb itself:
Like the rear overhead lamp, there is a template molded into the headliner for these, as well:
Just cut the hole like so:
Insert the lens from the bottom:
And secure the bracket:
Finally you swap the wiring harness. At the front where it leads into the A-pillar, the harness and rear washer fluid feed tube are taped together with mounting tabs. Make note of the mounting tabs' positions and remove the tape. Replace the tabs if they're broken:
Then just remove the OEM harness from the headliner (it is held in place with hot glue), and replace with the new one which, depending on your project, may be with or without the vanity lamps. Secure with hot glue.
Reinstall your headliner and there's only one more Euro part to go... the visors! Yes, the visors are different when you have vanity lamps... the mirror covers are recessed with sliding doors for two purpose: first, so the visor doesn't accidentally switch on the lamp. And second, the normal flip-up cover would block the light from the lamp. Here's what you need:
And that's it... you're good to go!