Telephone BASEPLATE -R126-, Removing And Installing, Cell Phone Mount: Notes
WARNING: This page does not describe the selected car, but rather 19 other vehicles, including the 2017 Audi S5, 2017 Audi A5 Quattro, 2016 Audi S5, 2016 Audi A5 Quattro, and 2015 Audi S5. However, it is still accessible from the selected car via links, so may be relevant.
-- Turn Off The Ignition And All Electrical Consumers And Remove The Ignition Key.