As in the title, I was fiddling about with airbox, when I've found that socket:



then next ones, a bit further towards the windscreen



and one in each corner, close to the windscreen





Can anyone shed some light please? As I was wondering if I could make some use out of any of those?

 

You can look it up on the Jaguar Heritage X300 Workshop DVD in the "Sedan Range Electrical Guide", based on the wire colours.

At a guess, heated front screen, EGR, secondary air pump or other such optional items.

I was once told the wiring loom was the single most expensive item in a car. I can see why they wouldn't want too many separate part numbers in stock and just put all the plugs on every loom.