BeKure wrote:Unfortunately the option to adjust the slider is not available in Waze when my iPhone is plugged into or connected via bluetooth to my car stereo.
Do you have "prefer bluetooth" selected because you want it to interrupt the radio or other audio source playing on your car stereo? If not, you can turn off prefer BT and if your phone is paired and connected to the stereo, it will play prompts over bluetooth streaming mode.
Prefer BT forces the headset-BT connection. This initiates the "phone call" connection to your car stereo. Many car stereos also have independent volume settings for audio inputs. My phone call volume setting is quite different from my FM radio or USB volume setting.
One last way to check out the Waze device output volume is to be at the main map screen. Wave your hand or 3-finger tap to bring up the voice commands prompt interface. Use the iPhone hardware buttons to increase the sound right then.