A6 4f radio clock defective

Hi!

I have an Audi A6 4F, manufactured in 2006. Since the time change, the radio clock hasn't adjusted.
I also no longer see the small radio tower icon on the display.
Yesterday, the radio receiver was already replaced behind the bumper, but the radio clock still doesn't work.

There are 3 wires at the connector, and normally there should be 5V coming from the instrument cluster, but I only measured 5V once for a few seconds.

Can someone tell me if the 5V needs to be constantly supplied? Then the station wagon probably has a problem.