radio confusion 78 300cd

[NC240D76]

I am not sure if this should be here or in the audio section but any later model advice will be worthless so here we are.
1978 300cd that I have had for several years and I am finally getting around to working on the interior. Jumped the rheostat and got the dash lights working, got a new switch panel that matched from a member here and ordered a radio from crutchfield since this car did not have one when I bought it.
I did some research here before starting and was very happy to find that under my shifter surround in the fader harness was both positive and negitive wires for both rear speakers, and they crackled when touched to a battery (9v). Tracing the wires a few inches farther I found both front speaker wires, positive and negitive, and had enough slack wire to pull everything out the radio opening. I fished around and found a red wire with electrical tape covering the connector, a bare brown wire and a taped up black wire.
I removed this section because it was not correct.

Thanks for any help

[NC240D76]

Please ignore the last part of C.
Obviously this would only work if I made a switched relay that connected the black wire to ground , not power.

[NC240D76]

This car has neither a cigar lighter or the sunroof so stealing switched power and a ground from there is out.

[NC240D76]

Never mind. I figured it out.