On a 1997-2002 A8 the fuse box is in the passenger side footwell. There is a small knob that must be unscrewed and the carpeted panel must be removed to reveal the fuse box.
Where is the thermostat located on a 2006 Chevy Impala?
Probably at the engine end of the upper radiator hose
On the 3.5L it's just inboard of the water pump, at the end of the lower radiator hose...