radio buttons 3-6-9 not working on XC90

it's more likely to be an electro-mechanical problem than a logic error. it's boring but: power down; pull the faceplate (you will probably need to pull the entire unit, unscrew the top or bottom plate of the casing to get @ the snap tabs which are the most likely fasteners for the faceplate, first); visually inspect the connections both electrical & mechanical. it should be obvious, esp. after you wiggle/operate these connections.

unless you know what you are doing & have access to replacement parts, you will have no use for a multi-meter. there are no more "Floyd's fix it shops". buy a new one! if you get a new unit similar to the old & keep the old, you will now have spare parts. i trick i have used profitably on a series of alarm clocks, which just don't seem to be able to survive my morning moods.

If you play cs #2 to the end, doesn't it automatically load cd #3 next?

depends on the setting -- shuffle, repeat or sequence.

i agree that brakes are important but they are also easy to do -- midas doesn't hire rocket scientists. you should already have all the tools. Volvo gives you a scissor jack & a lug wench. you should have a metric socket set. there is just one non-lug bolt. it holds the rotor in place when you remount the wheel. i think its a 9 or a 10. you can even use Vice-grips, for all i care. providing half a brain & a little knowledge, well that's on you.

don't get me wrong. a good brake job, like any other automotive repair is an art form. it certainly is for me & everyone else that i let touch Myst. we are just hard (impossible) to find, tough to beat (afford).

You need the control panel which is sold by Volvo. This is a common fault & corrected by replacing the panel

cool! do you have a non-volvo source of supply. let's face it. volvo control unit = $$$$$$$$$$$$ probably aftermarket complete radio/cd = $ i'd likely do it anyway. i just don't like throwing things away. RRR!

While I haven't opened this particular unit, cracked solder joints are extremely common on all sorts of consumer electronics and will cause problems like this.