DTC C1425: Open in Stop Light Switch Circuit: Wiring Diagram
WARNING: This page is about a different car, the 2009 Lexus IS 350 and 2009 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Stop Light Switch Circuit & Stop Light Control Relay Circuit - Wiring Diagram (1 Of 2)