radio wires

[acerimmer]

am trying to wire a radio in but some plank before me made a job hash job of wireing. in a nut shell, i still have all the wires for the speckers, but the other 4 are cut, i take it 1 is earth, remote, and positve and the 4th ???

the colour wires i have are
blue
green/black
yellow/green
red

does anybody know which are which, any help would be great it would save me alot of time with a tester and blowing fuses lol

its on a willy 3, if that will make any differenats

[Flan]

I'd guess blue is a remote or for dimming when the lights are on.
Brown earth
Red constant 12v
Yellow switched 12v through ignition

Flan