2010 Toyota FJ Cruiser Owners Manual - Page 229

3-1. Using the air conditioning system and defogger Rear window defogger This feature is used to defog the rear window. On/off Press the button to turn on the rear window defogger. The indicator light will come on. The defogger will automatically turn off after 15 to 240 minutes. The operation time changes according to the ambient temperature and vehicle speed. Pressing the button again also turns the defogger off.