No navigation audio when making a phone call

I have a galaxy note 9. When I plug the phone into my car with a USB cable and use android auto on my in car infotainment screen I do not get voice guided navigation from Google maps while making a phone call. If I only use Google maps on my phone screen and not my in car infotainment screen I can make a phone call and get voice guided map direction. I have had this problem in two separate vehicles so it's not a car problem. I have tried every setting suggestion I can find and still nothing. I know its capable of doing this because one time it actually worked but as soon as I shut the car off and came back later it did not work. Thanks for any help.