Mystery Radio Plug

In my last post I told you that I had got my car running again after sitting for over a year. Now I want to put in my new Sony stereo that I had bought before the clutch went out. I have read the Tech article by Brandon Coop. I have the old radio and EQ out. I have unplugged the factory amp in the trunk. I have found what I think is the "Secret" plug in the factory wiring harness.
It is the black plug in the upper right hand side of the included photo. The gray one and the lower black one were the two plugs that went into the original radio. The upper one was not plugged into anything. I have an adapter wiring harness that I got from Wal-mart. Is the upper black plug the one I put the adapter into? Should I do anything with the other plugs? The tech article confuses me on this. It reads like you use two adapter plugs. If you do what is wired to what? I am trying not to fry my "New" stereo, which is probably over a year old and out of warranty,or my cars electrical system. Anybody that has done this lately and could help me out I would appreciate it.
Thanks
B D
PS I do not know if photo uploaded. I will try again if it did not

You can put it into other programs like Paint and shrink it. If not, send it to me and I'll butcher that hog

Here is BD's Pic.
http://natomessageboard.com/uploads/0000...oplug1.JPG

Yep yep! I had the premium sound but no EQ. I used the alternate plug after unplugging the amp. That plug is pigtailed to the circuit to the amp through the speaker connections. When you take the speakers out you'll notice that each + and - has 2 wires; one of those 2 is a direct no amp shot to that 2nd plug. EVTM shows this also.

BTW, if you are not wanting to run speaker wire for a sub and have a speaker level input amp, you can use/tap the amp speaker plug since it ultimately "reverse" connects to the alternat head plug. I did this but didn't think it sounded right so I ran monster cable for the line in. Turned out to be a blown woofer in the sealed box (couldn't see it).