I have replaced switches and bulbs on head units (not that one, however). First, you'll need the parts. Panasonic has great customer support for this, but I don't know about others. Parts may be available at a local electronics store, but without specifications often they, nor you, can tell what is the voltage for the particular bulb (not always 12).
Once you have the parts, you'll have to open the unit and get to the PC board (or whatever) and then remove the offending part and replace with the new. You'll need a soldering iron (15 to 40w is plenty, adjustable is better (I have a Weller WLC100, adjustable from 5 to 40w, that has served me well, <$40.00)), solder wick to remove the old solder, some small diameter (0.031") rosin core non-corrosive non-conductive solder with a low melting temperature (~360'F; SN60 or 63 should work).
Practice on some PC boards if you can. If you mess-up, well it might be time for an upgrade.
I'd give this project a three-beer rating.