My navigation screen is black and no radio

I would say to check for blown fuses, but if you are seeing a light flickering, it doesn't appear that has any relevance. Do you have any components -- like a phone or other device -- plugged into the vehicle, or even engage with Bluetooth? If so, disable this and recheck operation. Otherwise, testing will be needed; it could be hardware or software related, so it's hard to say if you need "new" components. https://repairpal.com/repair-shops/volkswagen-repair-and-service-in-brenham-texas