I want to set my clock in my Volvo S40 54 - 2004 Volvo V40 Wagon

Check the owner's manual or go to the dealer service drive. They should be happy to help you.

Unfortunately, this seems to be a common problem. The fuse will likely be for part of the instrument cluster.
If you aren't seeing any other issues, then it's probably a problem with the clock.
On the other hand, if you are seeing other issues, there is a possibility that it is the processor (yes, there's a separate processor for dashboard functions and instruments).

What model volvo? I'm guessing it's a fuse, so maybe it's as simple as removing the fuse cover on the side of the dash, accessible when you open the driver side door?
The inside of the lid will have the layout of the fuses so you'll see which is for power locks/clock.

It sounds like the memory's low voltage supply is cut off.

There is a small plastic rod coming out of the instrument cluster near the clock the same as the one for resetting/toggling the trip computer. Turn and hold it clockwise or counterclockwise, that will adjust the time.

Maybe can find information about this in the Volvo Owners Manual

Hope helped.

remove your combine instrument,check bulb for clock,,replace if the bulb burn or failure.

in the radio display

Here's how to set the clock on a 2004 Volvo V40. Rotate the odometer stem to the right or to the left and hold it without pushing it in. The clock will start to move slowly then speed up. This seems to have been left out of the owners manual. Hope it helps.

If there is no display, you could check the fuse box? To set the time manual page 38. number 13. twist and hold to change the time.