The following appears to be the connections after cable tracing and multimeter testing
Large plug
Left Front Speaker
blue
Right Front Speaker
brown
n/c
n/c
??????
red/yellow
power ignition switch
blue/brown
Left Front Speaker
black/white
Right Front Speaker
black/red
Aerial Motor
red
Unswitched battery
purple/black
n/c
n/c
Small plug
n/c
n/c
Right Rear Speaker
orange
Left Rear Speaker
black/yellow
Left Rear Speaker
light green
Right Rear Speaker
purple/black
The only one I have not been able to identify is the red/yellow lead.