Hey, the instrument panel (speedometer, tach, fuel gauge, etc) does not illuminate and also the lights that light up the hazard switches, air con, defroster, etc. How to fix?

Also, what is weird, is that when I turn the lights on and off and then back on, the lights come on for a split second, then they turn off again really quick. What's going on?

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1990 Mercedes 300 SEL (320,000 miles)
1994 Mercedes E420 (140,000 miles)