To prevent malfunction of the switching diversity antenna system of the vehicle, which always results in poor FM radio reception, remove the negative terminal of the vehicle battery for at least 15 minutes before the Z-E7015S is installed and connected.
Connect the antenna wire with black housing and make sure, the Z-E7015S does have the “P.ANT” wire connected correctly to the vehicle harness.
Go for a functionality test by a station seek, where at least three relatively weak radio stations get saved and tested with a quick drive, validating if the switching diversity system does work as designed.