FixVault

System Diagram

WARNING: This page is about a different car, the 2007 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Cruise Control System Diagram
G05273607Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Communication Table: 

COMMUNICATION TABLE

Sender Receiver Signal Line
ECM Gateway ECU CRUISE main indicator operation signal CAN
Gateway ECU Combination meter CRUISE main indicator operation signal BEAN