I'm not 100% sure on 06
but on older models the colors were

Dark green RF +
light green RF -
Tan LF +
Grey -

There are usually more than one wire of these colors but all 4 of these will
be all in a row
It's possible the wire colors have changed so use this as a guide. if the
wire colors do look different you can remove the door panels and see what
the colors are at the speakers