Radio wiring

Making sense of the radio/stereo wiring was a challenge.
It appears that several different units have been installed over time, each adding more and more wires, while butchering the original harness.

Butt-splice, over butt-splice. I also found several of those screw on connectors used in household light switch installations.

I decide to remove everything, and start fresh. It turns out I had random loops of the some wires going everywhere. 4 grounds and 5 power wires ???????? And they all came from the same spot!

Ahh yes, much simpler, and clean also. A bit of solder and heat shrink does wonders.
The red, yellow, black and white connectors go to each speaker after exiting the Front/Rear fader. The original radio (which I did manage to find at a junk yard) has only 2 output channels, thus needing to go through the fader/mixer. It is not needed if installing a modern radio, since they have at least 4 outputs.

  
I simplified and coloured in the factory manual wiring diagram. Pretty simple once all excess wires were removed.   Unfortunately I did not have a proper plug for the back of the radio, but the various female connectors I manged to scrounge do the job just as well.