When you accessed the Settings tab in Sync, did you scroll to the right? There should be an icon on the second screen where you can enable Android Auto. I need to take a look on my car to see exactly where that is.
Regardless, just try to connect your phone to the car and see if it triggers any Android Auto prompt in either your car or the phone. On my phone, each time I connect it, I see a prompt asking for connection mode between: charge only, folders etc. I always select charge only, but it is really not needed, Android Auto always starts regardless if I select something.
Also, the cable is important it seems. I remember a number of people had issues with the cable, myself as well, and therefore I have used the original Huawei cable. AliExpress cables simply did not trigger Android Auto.
Please take a minute to fill out your car model in your signature, it helps us when answering your questions and saves you having to type it in all the time. Details can be found here.........Welcome to the Forum, Please Read