I found a quote here:
https://www.bimmerfest.com/threads/s...nsors.1296895/
"Here is the wiring diagram for the TCU (Telematics Control Module) that controls telephone calls via bluetooth connection with your cell phone, or the emergency service (SOS) calls to BMW Assistance. You will note that there is a "Mute" connection from the TCU to the Radio (N9), Pin #10 of Connector X13812.
https://www.newtis.info/tisv2/a/en/...ectors/connectors-from-x4/x4553-x4553/oMvixPX"
Of course the diagram is long gone.
Can anyone help please?