Was putting in a new wiring harness to the head unit. radio hasn't worked in years. Found this among the wiring. It had a ground from the head unit hooked into it, otherwise i'm not sure anything was even plugged into it. An amplifier was installed a while back, which i think is why the radio wasn't working, so i just wired everything back like stock and the radio works now. But I have this and all the amplifier wiring back there left over.

 

Kinda looks like the harness for retrofitting in an XM radio or ipod adapter.

 

Looks like a normal plug and play head unit adapter to me.

 

If either of those are it, that would be good. Everything works without it so just planning to scrap it. I wonder if it was maybe leftover from the OEM head unit? It was just sitting back there with the current head unit's ground electrical taped into it, which is odd since this wasn't grounded.