Good afternoon from Southeast Tennessee!!

I too have had the BAS / ESP light on and the "light out" lamp lit at various times. I'd start the XF, no lights, press the brake pedal, lights came on. Somewhere else on the forum I read that the owner was wiggling fuses while his son pressed the brake pedal. Fuse #2, located in the fuse box in the dash, was the culprit. I too replaced the brake switch, not too difficult BUT, I'm not as young as I use to be trying crawl under the dash. That didn't fix my problem. So I played with fuse #2. Didn't need to change the fuse, I removed it, rotated it 180 degrees and reinserted. No more warning lights on dash, brake lights illuminate and cruise control works.

As I was looking at the fuse to see if it was shorted out, I noticed that the fuse and the connectors in the box are aluminum. Aluminum is an awesome conductor, it's lightweight and inexpensive. BUT ...
As an engineer at Caterpillar we had very large testing stations that would cycle the components after manufacturing as if it was installed in a machine. These stations had very large pumps and motors attached to test the component. Many were 400A motors. One test station was being repaired and it took a while. The main feed for the machine was connected to a 2400A aluminum main buss. As the machine sat, the aluminum cooled and the main connections were not tight anymore, no one checked them. I was doing field work, near the machine, and the electrical cabinets were on the mezzanine approx. 13 feet above me. When maintenance fired the machine back up, the connections being loose arced and a 4 foot fireball shot across the room, over my head. The loud bang was close to a cannon sound.

Bottom line to that whole long story, aluminum is great but. My XF will be 20 years old in Sept of 2023, and those aluminum fuses have been pretty much undisturbed. They'd heat up, then cool down. It is highly possible connections aren't quite as tight as they were when the XF was manufactured. To date, I've removed and reinserted fuse #2 (BAS/ESP brake light) & fuse #9 (remote fob not unlocking doors). All works fine now. I haven't touched any other fuses but, I think that will be the first thing I do should I have any other issues.

Just thought I'd share.