Only Front Switch Cannot Operate Rear Sunshade: Description
WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
A rear sunshade switch signal is sent from the No 2 console switch (Integration control & panel) to the No 1 console switch (combination switch) Then the signal is sent through LIN communication to the outer mirror switch, which then sends the signal through CAN communication to the rear junction block ECU, and the rear sunshade operates.