S40 2003 dashboard illumination - dim
 

We've just started using our first Volvo - an S4 (first series). The car is in very good condition and everything works. There is a knurled rotary adjuster to alter the brightness of the instrument panel, but all it seems to do is alter the brightness of the red pointers and nothing else. If the figures on the dials behind are altering then it is such a small difference that it is difficult to decide if anything is happening or not. The two digital displays (odometer and clock) certainly don't alter.
With my old eyes, I could do with everything being brighter and can't believe that Volvo took the trouble and expense to design in a brightness control... but one that only affects the pointers and not the stuff you actually want to see. In daylight all the dashboard information (dials and digital) is dim and hard to read. Any opinions on how the dashboard lighting can be bettered?

It maybe that some bulbs have blown,or become blackened ?

Pictures please

All lights on my dash dim - that is everything in the drivers display and all the centre panel including the radio. The only lights that do not dim are the switches on the doors and the red triangle on the hazard switch.

Now that you've mentioned the radio and the red hazard triangle, I recall that they're not lit up at all. Clearly I need to check a wiring diagram to see if (hopefully) a fuse controls all the dud items though not the pointers. Replacing a fuse would be an easy solution, but anything beyond that is likely to be a bit tricky, especially if it involves going behind the dash. Once upon a time I'd dive in, but nowadays those days are long gone!

OK, done that with a downloaded pdf. Completely incomprehensible..!

Normal Cars that age light bulbs have broken filament

Does that mean that if one fails then none of the others will work... even though those others are OK? If not, then all would have had to have failed, which seems unlikely.

Each bulb can fail independently and not affect the others.

That suggests it's not a bulb fault, but something further upstream that affects all. I've a Haynes manual – so that's better than nothing – and although anything electrical is bamboozling to me, I can see that the things that don't light up all run off one section of the diagram. I've no idea if that's just a diagramatic representation or if it actually is one unit, say a fusebox or something. Whoever compiled the diagram didn't trouble themselves to identify it.
Unfortunately, the temp gauge and fuel gauge are in that section as well but both work fine, whereas the radio illumination that doesn't work is in a different section altogether. However, I do know that auto electrical diagrams for what seems to be your car aren't necessarily completely accurate – the manufacturer often makes changes to the way it wires things even in the same model range.