If you are running version v1.46.2.6s and find that your DLCs are not showing up, you can verify them directly in the game:
: SCS Software added a new, previously unreachable area in Spain, including a new highway exit and explorable roads near Madrid. ETS2-DLC's v1.46.2.6s
: A new way to track your progress, including a collection of "viewpoints" and photos from across your DLC expansions. Managing Your DLCs If you are running version v1