Adding some more info on this topic:
Symptoms: First, I noticed the driver's seat and steering stopped moving back/up when I shut off the car. All seat memory and mirror memory ceased working. Seat movement still worked via the seat controls. All fuses were good.
A few weeks later I noticed I could no longer move the steering wheel more than a millimeter for each press of the tilt/tele switch. That means it would take about 10 minutes to move it all the way up or down, 1 millimeter at a time. Thought this could be the motor in the column which is a known failure point, but didn't chase that down due to the other seat/mirror symptoms on that same circuit.
Another week goes by and the driver's seat stops moving completely, except for a millimeter movement for every 2 or 3 pushes of the seat controls. A day later, there was no movement at all.
Pulled the module shown below. The part number on mine was "61.31-4 318 615" which has been replaced by part number "61.31-7 119 867". This is for the "ACTUATION UNIT LEFT" a.k.a., the power seat memory module.
This part used to be over $500. My local dealer had 1 in stock for $369. Bav Auto could order me one for about 10% less. However, the best price by far was from
Morristown BMW which was about 30% less than Bav. Email Morristown for an exact quote.
Reinstalled the module in 2 minutes and now all seat memory is back, steering movement is normal, and mirror memory works again. Expensive part but easy to fix.