Check the bulbs. I think the cluster lights are 3 watt bulbs. I just replaced them in my 126. I removed old 3 watt bulbs and installed new 3 watt bulbs.
Old bulbs get dim over time. Do not put in over watt bulbs or you will melt the plastic.

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2009 CLS550 55,000
2004 ML350 144,000
2004 X5 95,000
2002 X5 165,000
1996 320S 155,000 (sold)
1991 190E 192,000 (sold)
1989 300SE 160,00 (sold)
1984 300D 210,000 owned since 85, (sold)
1984 300SD 160,000 (sold)