ok well waht i did (have 5 cold catodes in my car (2 12" footwells, 2 4" in back seat, and 1 4" behidn ac) All of the postivices (yellow wires) behind the cig lighter like in the installs here on ecelica.) Now for the black one on all, you need to gorund it to the frame somehow). What i did is: tkae off the plastic under hte steering wheel. ITs liek 3 bolts. Now with that off ther eis a big metal plate behind it. I grounded all of them to that (as well as my S7 gauges). Justed tied them together and hoked them to that blate at one of its bolts. Now everhyting will work great. Jsut amek sure they are firlmy attqched to that plate. I jsut wedged them behind one of the sides with teh bolts
I forget to detached neg termanal but i woudl suggest doing it. If youa hve any other questiuons PM me.