This works in Android Auto. Follow these steps:
1.Launch the Android Auto application on your smartphone
2. Tap on the hamburger menu icon in the top left corner
3. Select the About option
4. Tap repeatedly on the About Android Auto portion of the heading until a pop-up states that Developer settings is enabled
5. Go into the Developer Settings option (the pop up tells you where it is) and enable Unknown Sources. It's at the very bottom.
Then open Spotify, start playing something. The Android Auto app will detect Spotify exists and from that point on you will be able to fully control Spotify from Android Auto.
1.Launch the Android Auto application on your smartphone
2. Tap on the hamburger menu icon in the top left corner
3. Select the About option
4. Tap repeatedly on the About Android Auto portion of the heading until a pop-up states that Developer settings is enabled
5. Go into the Developer Settings option (the pop up tells you where it is) and enable Unknown Sources. It's at the very bottom.
Then open Spotify, start playing something. The Android Auto app will detect Spotify exists and from that point on you will be able to fully control Spotify from Android Auto.