That's how mine started.

I got the motor and mirror replaced a while back. The motor is really easy to remove. Once the mirror glass is off you will see the motor which is held in place by a few Philips head screws.

I had to remove another mirror on another car and came up with my own method for not cracking the glass.

Find a piece of long flat plastic that is used to package boxes/parcels. Cut into 2 pieces. Slide the plastic pieces behind the mirror glass about 1/3 of the way in on either side. Put a towel on the mirror glass and then grab the free ends of the plastic and pull slow but hard.

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2009 135i M Sport Convertible
2008 X5 3.0si
2003 E46 318Ti M Sport Compact - donated to parents
2003 116i Hatchback - donated to brother
2002 316Ti - Sold
2000 318ci M Sport - Sold
1998 318i Sedan - Sold