To remove the cover you will have to fold the mirror in. That will get you to the inside. Once there you will find a spring latch. Pry the spring latch and it will release the cover. When my mirror burned out it would not fold. I carefully folded the mirror in by hand. After replacing all the internal parts, all of the features on mine did not work. I burned out a small cuircit inside the memory control board, under passengers foot rest. I replaced the burned curcit and all is well again.

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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)