Reverse Shift-linked Function of Power Mirrors do not Operate: Description
WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
When the reverse signal is sent from the ECM through the multiplex communication line to the multiplex network door ECU front LH (driver door ECU), the ECU activates the outer rear view mirror LH and RH reverse shift-linked function.
HINT:
The reverse shift-linked function will not occur when the mirror master switch is in the neutral position (OFF).