If you still need it, Black is negative (as guessed!) ummmm....
I will have to go home amd check it out, as I have a pioneer head unit and works fine. I installed it myself. The factory harness does have illumination.
I'll post ya the details tomorrow ok.....
EA Fairmont Ghia : 3.9L MPFI, 2.5" cat back sports exhaust, K&N panel filter. Pioneer head unit, pioneer 4" three way fronts, Pioneer 6" 3 way rears, 2x 12" subs, blue interior light.
My main pride and joy : '76 XB Fairmont GS, 250CI, 140,000 Km and all stock.... for now! (Factory air-con on the way)