So last month ,when locking my 2016 rx450 i noticed my drivers mirror was not auto nor manually folding back. Getting back inside i fold that my drivers door rest multifuntional control unit no longer operated my drivers door. However switching over to the passenger side, i was still able to fully control the mirror in tilt and fold. (Surprisingly both mirrors still displayed the orange Blind spot monitoring warning). I had also lost all functions of the 3 memory set buttons. I could manually move the drivers seat in all directions to where i wanted it, but not from memory switches. The drivers mirror offerred no resistance, like it had suffered terminal damage from being snapped fully back going thru automatic car washes. Looking on this forumn i tried all the resets of the seats like fully back, fully forward, up,down etc but made no difference. I even took the full door panel off (easy) and re-pushed together every visible connection, but made no difference. Was even lent a full multi function control unit from a friends rx and still made no difference. So this weekend in the glorious sunshine i crawled underneath my dash to access the narrow rectangular fuseboard. Using a pair of long nose pliers rather than the official supplied Lexus plastic fuse removal cramp (grip failed so quickly) i proceeded to remove every single fuse then refit, pushed home firmly. Upon getting out of my car after finding NO Blown fuses i gave up. Pushed the locking keyfob and both mirrors folded back. Jumped back inside and all controls to mirrors and seat memories were back to as good as new. Dont know what/fuse it actually was, but just wanted to share my experience if may help somebody sometime.