Obviously the first thing you'll want to is check all the fuses, not just for intactness, but for any corrosion that could render them unconductive. Probably be a good idea to check the incoming side of the computer fuse for power, too.
If the fuse panel is good and powered up, then start unplugging connectors and give them a shot of contact cleaner (or at least some WD40) Test for voltage as you go along, this might require a wiring schematic which should be in the manual thread.
Hopefully it's just a minor corrosion issue which this will clean up; you might have to inspect back into the digital panel as well. If it lives outside in the weather this would be more likely.