Tricky question

Hope of you more experienced owners can help me with this issue.
I use Google Maps as my main GPS, and it works great.
My Santa Fe has Blue Link & my iPhone is paired.

Now if I start Google Maps before I get into the vehicle the Google Maps voice comes through the car radio speakers. Very cool.
But, if I start Google Maps while I'm in the vehicle, all audio is silent.

So, my question is, how do I get Google Maps to pay the audio through my vehicles speakers ALL the time???

TIA,