A good way to label vac. lines and wires is to use tape and put numbers and letters on it. For example: Mark a vac. hose with "A" and mark the spot where it plugs in with the same. If you use letters for vac. lines, use numbers for wiring. If you somehow get past "Z" continue with "AA", "BB", "CC", etc. I learned this from a Master Auto Body Tech. Never had a problem since.