Holden SV6 2010 Rear door speakers,Are they hooked

up from factory! There are speaker hole covers there BUT havent yet checked if they come out with factory speakers in them. The only sound we get comes from the front dash and front door speakers. We have looked at the settings on the digital display and no sound will come out of the rear door speakers. Any ideas!

So when you go to the audio settings and turn the "Fader" from front to rear, you get no sounds at all!