Trailer wiring 2010 Legacy Wagon

Hi,

I have a 2010 (or 2011, I can't remember just now) 2.0 diesel Legacy Wagon, Swiss edition.

I installed a Westfalia hitch and basic functions of the 13-pole plug electric harness with no issues, and they all work.

But I have questions about the non-standard circuits of the electric harness. The instructions are sparse.

If anyone could help I'd be very thankful!!:

1) I couldn't figure out which wire to cut for the fog light, so I haven't installed that part of the harness. It's supposed to be above the hatchback door, but these wires were inaccessible behind the roof insulation, and pulled very tight so I couldn't get my hand in. Then I couldn't get the fiddly trim piece above the hatch back in !! Has anyone done this?

2) To finish the installation, I need a constant 12V for an electric trailer brake and a 12V on a relay for charging a trailer battery. I have the Westfalia harness kit with 6 meters or so of cable for each circuit. Do the relays and fuses go in the driver's footwell area or under the hood/bonnet? What am I facing as far as routing the cables -- under the carpet, in a channel in the unibody, etc.?

Thanks!

Jeremy