2001 XJ tail lights and dash lights not working.

As the title says. A friend of mine as a 2001 XJ yesterday she started it and turned the lights on. She noticed the dash lights were dim. She turned the dimmer knob and the dash lights brightened as they should then they went out. She didn't hear a pop or anything that would lead her to believe a blown fuse, but she checked them anyway and nothing was blown. She is an electrician so I trust her skills on electrical testing. I did some surfing and found stuff on older XJ's and went through some checks with her but I'm not near by so it is hard to even think of what to look at without seeing it and getting the ah ha moment.

Any ideas.

2001 XJ tail lights and dash lights not working.