Need an update after no work, works, sometimes, etc. Now what works and what does not work? When you say you "clean" something, what? why? how?...don't forget we gotta ask questions too. Lets take one thing at a time if possible. So how do you know something is going out if you don't test it. Regarding brake lights still not working, you say you ran a test ground wire to them, you DID NOT say they have hot to them, you just said no 12V at switch then yes 12V. What I do is get a tested bulb in my hand and put known power from brake switch to each contact, of the two filament brake bulb, and touch the bulb case to a clean ground while someone or a 2X4 holds the brake on. If it lights I know I can work from there. Then if I place it in the socket using the same hot I get more info. You can do all the checking with a meter or light if you have that.
