You said the tail light stays on without hitting either brake. First are you seeing the "tail light" or the brake light on? If it is your brake light that is staying on check the adjustment of the brake light switch on the right side by your foot rest. Some times on older Hondas they vibrate loose or just get out of adjustment. Also make sure the wires are plugged into the correct leads. If you bought it used someone may have guessed at what goes where? I've owned a lot of Hondas and I almost always find the wires screwed up.