If the mute wire is a negative output,
Pin 85 - negative output from Mute wire
Pin 86 - +12v (you could use constant, accessory or remote wire)
Pin 87A- cut remote wire from your source
Pin 87 - not used
Pin 30 - cut Remote wire to amps
If the mute wire is a positive output, then pin 86 should be connected to negative ground.