The Battery is on the far right passenger side in left hand drive (LHD) vehicles, then next towards center is the box containing the RCM, the ECU, and a couple other components. Then across to the other side close to center is the brake booster and outboard of that brake booster (last thing before the drivers side fender) is the rectangular black box under hood electrical fuse center holding the majority of the fuses for the various systems in the car. That rectangular box opens by squeezing the tabs on the top front of the box, and lifting that cover off. In there, on the inside of the cover, is the legend of all the fuse positions and what they are hooked into. Now that you know where this box it, I suggest you download the service manuals for the car and research what circuit you might want to 'tap' into. I would limit the search to accessory items like the seat heaters, motors, and such. I would not tap into any critical engine management or safety airbag/brake power lines or systems. This is where your research of the type, current requirements and accessibility to the wiring coupled with the car electrical systems and locations of easy access for where you want to tap in. As a minimum, you have to at least know where all the basic systems and fuses are located, and which ones to stay away from. If you have any reservations about researching/looking up the info you need, then zip to one of the bi-yearly tail of the dragon meets and ask around for a little assistance. You can also try to meet up to one of the many XF tinkerers located near you. I am sure you can find someone who can assist you in accomplishing what you want to do. Good luck in your research and modding! Oh, also, you definitely have to start downloading a few of the .pdf's from the site. I recommend the first one be the service manual, and study it relentlessly.