Hello MQZ4:
Welcome to Pprune, I notice that your question is also your first post here in the forum.
The "what the heck does the + symbol mean" question comes up about once every 18 months or so, kind of like a lunar eclipse
. There is a longer post about this, including some good pictures of the front and back sides of an electrical panel with a + symbol on it, at this link:
Small crosses drawn all over cockpit panels.
If you don't want to go read that whole discussion, I have reproduced the photos below, they are pretty much self-explanatory.
Again, welcome to the Pprune Forums.
Michael
