What is the U-Shaped black wire from a CD car deck? Also, there is no orange/white wire??

Question

I just bought a Pioneer DEH-2000 MP car deck for my 99 honda civic, and I don't know what to do with the black wire. It's end is 'U-Shaped' and is supposedly the ground wire, but in the original setup (another aftermarket CD deck was installed), there was a black wire hooked up to the black wire. I think maybe I remove the U shaped metal piece and hook up the black wires??

Also, in the original setup, there is an orange/white wire from the car, and from the previous car deck that was hooked up, but my new Pioneer doesn't have an orange wire. Do I just leave the orange/white wire from the car hanging? (It just doesnt make sense why there wouldnt be an orange wire)

Answer 1

The loop is for mounting the ground wire with a self tapping s***w to a strong metal surface of the car because the radio draws to much current for the other ground wire it wants you to ground it yourself.The orange and white wire sounds like a dimmer wire so when you dimm your Gage lights at night the radio display also dimms.Not important

Answer 2

before i hooked up the ground on the radio to the black wire in the harness i would check to make sure that it is the ground wire or i would tape it off and ground it using the wire with the "u" shaped connector

and as a rule the orange/white wire is for the dimmer (when you dim the instrument panel lights it dims the radios lights also) but most aftermarket radios don't use it- tape it off