RepairPal Certified shops can diagnose and repair your 2008 Volkswagen Touareg. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
No switch, it may be a bad screen or head unit. If it is you can find these used on ebay. Best to have a complete diagnosis in case it's wiring or another electrical issue.
https://repairpal.com/repair-shops
Alex