Mazda Mazda3 2019 Owner's Manual page 390

Interior Features
MZD Connect
▼ Audio Remote Control Switch Operation
The audio remote control switch is on the left side of the steering wheel. You can operate
the audio unit from the steering wheel.
The shape of the switches differs depending on the vehicle model.
No. Item
1
5-20
Volume adjustment button:
Press the (+) or (-) button to adjust the volume.
If you adjust the volume during a voice guidance, the volume of the voice
guidance changes.
If you adjust the volume while making a hands-free call, the conversation
volume changes.
Explanation