Hello , I have a new Tiguan trend and fun 2.0 and my dash light and radio won't work.

Check the manual and find the fuse box or boxes. find the dash lite fuse, it may say " interior illumination" If it is good check also the radio fuse.
If the fuses are good, you have to visit a wv dealer for detailed fault finding.
If the car still have warranty, don`t mess with the electrical system.
The car also have can bus electrical system, and it can go wrong when you try to fault find your self.

The fault could be the light switch, fuses, the radio.

Here is a fuse list for a golf:

http://mit.edu/dennis/www/vw/fuses.html

Check the Fog light relay, instrument panel light dimmer switch fuse.

Good luck