About to wire-up the new head unit in my '98 GS400.

I believe two of these below are power (D-4) and accessory (D1)
Is (D3) my ground wire? Or should I just run a ground to the chassis?

R5 (D) RADIO AND PLAYER
(D) 1–GROUND : Approx. 12 volts with ignition SW at ACC or ON position
(D) 4–GROUND : Always approx. 12 volts
(D) 3–GROUND : Always continuity

 

Typical color coordinating is blue for ACC should be ran to your ignition fuse if your aftermarket harness doesn't work....sometimes red 12 constant has to be split from harness to main radio fuse...I would suggest to ground 3 ways through the harness...to the case of the radio itself and to chassis