Mirror Heater does not Operate with Rear Defogger Switch: Description
WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.
w/ Navigation System
When the window defogger switch, which is built into the multi-display assembly, is operated, the operation signals are transmitted to the A/C amplifier assembly through AVC-LAN and BEAN When the A/C amplifier assembly receives the signals, it turns on the MIR HTR relay to operate the mirror heater
w/o Navigation System
When the mirror heater switch, which is built into the integration control and panel, is operated, the operation signals are transmitted to the A/C amplifier assembly through AVC-LAN and BEAN When the A/C amplifier assembly receives the signals, it turns on the MIR HTR relay to operate the mirror heater.
NOTE:
The power mirror control system is a part of the multiplex communication system. This system features shared communication wiring that reduces the wiring complexity of the communication lines. The first step in any repair is to confirm the proper operation of the communication system. Proceed with troubleshooting after the communication has been verified (See
HOW TO PROCEED WITH TROUBLESHOOTING
for Multiplex Communication System ).