I'm installing an Alpine 9883 in my 06 non-bose 350z using a Metra wiring harness. I have two wires left to hook up, one on the Alpine harness labeled "ground" and one on the Metra harness labeled "amp ground." My question is do I just need to tie these two together, or do I need to tie them together and ground them to metal on the car, or do I just need to ground the headunit to metal and forget about hooking up the amp ground?

Also, my metra wiring harness has two plugs, but I noticed when I unhooked my factory deck that my factory radio has 3 plugs going into it, the third one being a smaller plug on top that doesn't mate up with any of the metra stuff. Do I just leave this unhooked??

Thanks for any input guys.

 

your last option "ground the headunit to metal and forget about hooking up the amp ground"

the last plug is for the steering wheel controls which you need a pac-swi for

 

Sounds good. Thanks for the fast reply!