I'm only able to view 4 total playlists from Google Music on Android Auto. I can see them fine on the phone, 2 of them are automatic ones "thumbs up" and "last added" playlist. The other 2 are ones I made, which is great. I have a 5th playlist that I want to use but I can't see it on Android Auto at all. I feel like I should be able to scroll through the playlists but nope, only those 4 get displayed.
All 3 playlists were made around the same time, and it seems like the 2 playlists are displayed because I made them first. The 3rd playlist I made not displaying seems like a bug, otherwise this is just crazy to limit it to only displaying a few playlists and not providing any kind of option to select which ones to display.