Google Maps should start talking. Step 3: Turn up the volume in the Maps app. On your iPhone or iPad, open the Google Maps app . Tap your profile picture or initial Settings Navigation settings. Choose Louder. Step 4: Switch to your car speakers. You can hear voice navigation from your car speakers using Bluetooth or a USB cable.

​https://support.google.com/maps/answer/11523237?hl=en&co=GENIE.Platform%3DiOS