I've just bought a molex adaptor and I realised that one of the holes from the adaptor doesn't have a conductor through it(it's just plastic). I've tried the adaptor anyway on my dvd writter and it work's. I even connected the other 3 wires without the faulty wire and it Still works. My question is.... What is the purpose of that wire and if it's safe to use the molex adaptor.? I'm talking about the black wire near the yelow wire.
It`s just the way it`s wired, molex plugs drive a device that require a 5v power feed or a 12v power feed. since your device is a cd or dvd rom drive it requires a 12v DC feed. it`s fine don`t worry. Black, red = 5v feed. black, yellow =12v feed.
normaly two blacks and a red and yellow for 12v and 5v feed from the molex connector.