[Pops944]

Not sure how much this will help, but this is what I could find in the shop manuals for the '83:
red/blue wire comes from the ignition switch through the radio relay
red wire from the radio fuse
white wire from/to the antenna
brown wire to ground
speaker pairs as follows;
there is a brown wire for each channel (left - right) that goes to the front and rear speaker
left channel has a brown/red wire that goes to the speaker balance through a connector
pin 4 will be a blue wire
pin 5 brown going out to a brown/red wire to the front left speaker
pin 6 black going out to a brown/red wire to the rear left speaker
right channel has a brown/red wire that goes to the connector
pin 3 will be a red wire
pin 2 green going out to a brown/red wire to the front right speaker
pin 1 green going out to a brown/red wire to the rear right speaker

This isn't a lot, but it's all the manual says about the radio in the schematics. Good luck!