A8-6 & A7-7
WARNING: This page is about a different car, the 2001 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
Start engine. Turn headlights and defogger off. Set temperature to maximum warm and blower knob on HI. Place mode knob to foot/defrost mode. Witch coolant temperature less than 130°F (55°C), less than .7 volts should be present.