Androis Auto help with Google Maps audio
 

Just took delivery of our new 2018 A4 Allroad and love the vehicle. It replaces a 2007 A4 Avant. Having trouble with the Android Auto when using Google maps and a Samsung Galaxy S5 phone. With the radio playing in the background, when the map directions interrupt, the volume is very low. Have not found any way to increase just the Google maps audio alone. Went into Google maps and raised the volume level to the third (highest level) position but still no improvement. Phone volume control has no effect either. Did some research on the web and think this may be a Google problem but not sure if I'm missing something. Anyone else experience this problem and have a solution? Thanks.