What did you end up doing? It's good to have the "solutions" listed as well so later on down the road when someone encounters the same question(s), they can find this thread and go "Ah ha!"
I wanted to make sure I recalled how I did this proir to posting.
First, I disconnected the ground wire from your battery.
I already had my parking brake console removed for restoration so I was able to easily trace and access the two wires from the power antenna itself. You may not need to do this if you can locate these two wires up front or at the rear of your old sound system.
On the left side of the leg area on the passenger side, there is a carpeted fiberboard which covers the area under the console. Up near the front, after feeling through the carpet, I found one screw. After removing this one screw this plate came off very easily and gave me access to the entire area under the dash.
From the rear of the Pioneer AM/FM CD Player I installed, there were four wires, (aside from the 8 speaker wires).
-A black wire, which of course was the ground wire connected directly to the black ground wire from under the dash.
-A yellow wire from the rear of the CD player wired into a yellow ignition wire from under the dash.
-A red wire connected to the red 'hot' wire from under the dash. Also, one of the two wires that lead from the power antenna up to the front by way of the console is red. This red wire also connected into the red 'hot' wire. Therefore, I had 3 red wires all connected together.
-A blue wire, which is for an amp power booster and/or a power antenna.
The second of the two wires that ran from the power antenna up to the front by way of the console was, at least in my 1980, a light yellow wire. Up at the end of this wire at the dash was a fuse connection. I made sure this remained, with the correct amp fuse to insure added safety.
I connected this light yellow wire to the blue auxillary wire from the rear of the CD player.
I wanted to check and see if I had power prior to connecting the speaker wires. After reconnecting the battery cable, I turned on the ignition, hit the power button on the new CD player and it lit up!
After connecting the speaker wires and replacing the one panel underneath, this update was finished.
I did not need a wiring harness for this job, but since no two audio systems are alike, its hard to say if you would.
Oh. Don't forget to plug the large black main antenna wire into the back on the new stereo system!
