Carfan thanks so much. I've been wondering for a few days what was going on.
My symptoms are as you describe. 3-4 second squealing noise from the passenger footwell when the car is cold in the morning.
The blower motor I replaced recently and it did sound alot different.
One more thing to add to the list...
Silver 2004 BMW E66 / 745Li (DIYs):
ASK, Logic 7, blower, battery, guibo joint, active stabilizer bar bushings, diff oil, tranny sw update, vacuum pump gasket, window lift, a/c compressor, washer fluid reservoir, belt tensioner and deflector, crankcase vacuum hoses, crankcase vents, solenoid gaskets, headlight overhaul, ISM, hood lifts, driver mirror, sway bar end links, rear fog lamps, headlight washer, headlight vertical aim, VCGs
next up: P0492