When you say "doesn't work" how do you mean? If it's just that you can't see it then the halogen bulb behind it has blown. If you can see it but it is talking gibberish, then either the plugs to the back of the instrument binnacle or info centre selector switch are not tight (do your speedo and rev counter work ok?) or else the info centre PCB needs looking at - it's the smaller on fitted to the back of the instrument binnacle - and probably has broken/dried out solder somewhere.
If you go over to the 480 Europe forum (
https://www.volvo-480-europe.org/forum/index.php) you will find lots of stuff about this...
David