temp fitted my bros stereo a couple of days ago and we just taped it up (ours was spliced into the earth line running between the car plugs and the iso cable)...as it was getting a earth from the case being fastend to the body of the car, it wasnt needed. Im guessing as the iso is for all nissans there may be slight variations in the fitting methods...or maybe its just there to give you more options.
Though im sure others will have a more clearer idea if its meant to be used or not
you should be able to get away without it as the HU will earth through the aerial, however its recommended to screw it to the chassis (somewhere behind the HU) so that its a much better earth (and therefore more reliable). others might have a better idea of where to actually attach the earth if you dont have any ideas.
be happy you got an eye crimp on yours. right simple thing if you look at were your old lovely factory stero is fixed in you will see 4 screws 2 on ethier side. one side fixed into metal the other side into plastic. so just keep one of the old screws and screw the crimp onto metal side.
be happy you got an eye crimp on yours. right simple thing if you look at were your old lovely factory stero is fixed in you will see 4 screws 2 on ethier side. one side fixed into metal the other side into plastic. so just keep one of the old screws and screw the crimp onto metal side.