connector X18500, 54-pin

pin 51 - radio mute (apply ground)
pin 1 - (+) from microphone
pin 19 - (-) from microphone
pin 21 - shield from the coax cable from microphone
pin 37 - (+) for front speaker - this is BT speaker connection to come from the car speakers
pin 38 - (-) for front speaker

as always, use the given info at your own risk...