right iv got these wires by my alternator.. after i got my car back from a dodgey garage for a new engine in .. so iv pluged the red one in .. assuming the green wire is the live and the black one is the earth.. but whats the green plug for? been told it goes below the oil filter... but the haynes manual says thes one goes into the alternator but i cant find anything to plug into there?

any help much apreciated

any help much apreciated