What are these wires for? The black and grey empty plugs.

 

If the gray one is 6 wire it is for the rear sub and cig outlet. Not sure of the other one as the rear defogger and wiper are on the driver side.

 

The Grey one is 8 wire

 

Then no idea...lol All the sub ones I've seen are 6 wire. Is that the passenger side?

 

Yes, passenger side

 

Do your tail lights etc. work? I would say the 8 pin is tail/reverse/directional and the 2 pin is third brake light.

I don't have the tow package so I'm not sure what those look like so that's a possibility if your rear lights are all working.

 

This is a brand new 2015. Everything is working like it should ms the third brake light is connected. These don't go anywhere.

 

Sorry I can't help. Maybe they upgraded the stereo electronics in the back. No clue. Hopefully someone else will jump in who has those connectors in their rig. But based on location, and if you don't have the premium stereo, I would guess sub and charger outlet.