electrical problem?
 

'89 420 SEL with 182k

Recently the left two bulbs went out in the gauge cluster. I assumed that they were just burned out until two days later the radio display and the shifter backlight also went out. The radio is a Blaupunkt that is about 3 years old. I checked the fuses and nothing seems amiss. Is this just a coincidence or should I be checking something else. I have the bulbs on order - they should be in early this week.

Thanks for any insight.

Check alternator output voltage, shouldn't be above ~14.5vdc @ 1200rpm or higher.