USA-66 Wiring?

Hey there, umm wat year is ur car? i'm not sure how much the wiring differs from year to year but you might want to check this out if u have a 66.
http://midlife66.com/wiring/66stereo.jpg

Usually black is ground...
let me know how it works out cause I was thinking about purchasing the usa66 myself but a lot of ppl have been complaining about the sound quality with the older custom audio sound head units, some ppl say the 66 is much better tho

I would expect the OE radio to have a power lead that's energized with the ignition key, and a ground wire, plus a third wire connected to the dash light circuit, including the dimmer. You can use a test light or a voltmeter to figure out which is which.

I would expect an aftermarket head unit to have the same three wires -- an "ignition on" power lead, a "lights on" power lead, and a ground. There should be a fourth wire that's always energized, for the memory. I would also expect an additional line that's energized when the head unit is turned on, to power up an antenna and/or amps.

So it should just be a matter of matching the OE wire harness to the two power leads. I would use a sheet metal screw in the firewall or an existing screw or bolt for the ground. If you have no power antenna and no amps then you should tape off the extra wire running out of the head unit.

It's been a while, but I'm pretty sure I tied the black ground wire into the screw holding on the underdash light, as that is how the light grounds. The power and the memory wires I ran to the fuse box and found fuses that were under power when ignition was on and under power all the time, respectively. I hooked them up by popping out the fuse, wrapping the bare wire around the metal part of the fuse and popping it back in. Maybe not the best way to make the connection, but it worked fine and was easily reversible. The power antenna lead I just wrapped up and let hang as I had no power antenna.