WARNING: This page is about a different car, the 2022 Audi S3, 2022 Audi RS 3, 2022 Audi A3 Quattro, and 2022 Audi A3. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Removing Inner Insulation
Courtesy of AUDI OF AMERICA, LLC
-- Push the antenna wire -2- in the mount -1- all the way into the tool head.