Issue with Navi

Hi there.

I have some trouble with my onboard navigation unit.

When turning the left wheel for loudness the volume indicator on the screen jumps up and down which is very annoying.

When operating from the steering wheel the volume goes in steps upward or downward by clicking the button.

So I guess there is something wrong with the dialing wheel on the unit itself.

Does anyone know what could be the problem with the unit?


Kind regards