I bought the Nissan wiring harness http://www.crutchfield.com/S-5N22Q1F...00&I=120707550, to go with my new CDA-9856. There is a wire on the wiring harness called the "Amplifier shield ground" and it says to "connect to your new receiver's chassis." Does this mean I should connect it to the black ground wire of the headunit only? Or should I splice it into the headunit ground AND then connect to the vehicle chassis?

I assume if I connect it to the headunit ground only it would be using the stock headunit's ground which should work fine. Can these aftermarket headunits use the same ground as stock?

 

Like horsepower, women, and money you can never have too much ground!

Ideally everything would ground to the same mechanical point with very heavy gauge cable. For me I made that a point aft behind the seats near where my amplifiers mounted. From there I ran heavy cables to the two power amplifers and smaller cables to the CD-player, the brain, and the headend. I also grounded the headend to the dash ground located behind the LED gauge in the triple gauge cluster.

The "receiver's chassis" is the steel shell that makes your radio's outside.

The "amplifier shield ground" ... I'm can only guess that means the shields of the RCA cables. But I've never heard of that needing a seperate ground - nor ever seen one provided!

 

I called Crutchfield and they said since my car did not have the Bose or Navigation system I can tape off the "shield ground" wire. I just finished the installation and everything is working fine.

Same here, that ground was pretty easy to see. I had a time getting the bolt loose on it, though. Just about ran the screw out with a phillips head so I had to use a wrench!