7. Here is one reason why the Painless kit is so great. Every wire is labeled along the length of the wire. This tells you what fuse it runs to and what accessory it should run to. For example, this wire is part of the tail section of the harness. It is wire No. 949, a number you can cross-reference with the instructions (which also are online if you lose the originals), and then the insulation is marked "Left Turn (Brake)" to help designate it even further.