Randomly came across an old thread I made on stdrivers.co.uk and wasn't sure if I posted my ambient / submarine lighting here!
The newer Mondeos have it, as do many BMWs, Mercedes' etc so I thought I'd copy.
End result looks like this in the dark. Front photos were taken before I added front footwell lights:
It's not intrusive in the slightest but that's the closest I could get the photos to represent it.
And if anyone cares how I did it:
Make holes in ceiling light cluster:
Wire up 10mm orange LED:
In action:
Ran wire from roof down to the cigarette lighter illumination terminals as they light up when the headlights are on, which is how I wanted this to be powered.
I love how it looks at night and means the interior doesn't contrast too much against the light outside the vehicle. The orange LEDs are dim enough to not be intrusive in the slightest.
I used 8 5mm LEDs for the footwells, two for each footwell.
Some people might not fancy it but hey ho.