P1947K

I drive a 2008 Lexus LS460. The vehicle has a rear automatic blind/sunshade controllable up/down from a button on driver central control panel. It operates normally from the manual control or in the auto mode after selecting reverse and then back to drive. Recently it stops about 2/3rds up which can be annoying. The side arms are in a "V" shape and not straight and the top black bar is in the rear mirror line of view. Indication from Lexus service is a very expensive full system change out. Anyone had this experience? Are detailed drawings of these mechanisms available? Any ideas?