Originally Posted by nautiduck
I should know but what does ECO stand for?
ECO is short for Economy, ie good fuel economy.
The TCH also has an ECO button. ECO is Economy mode for the Heat and AC. It disables the air vent electric heating element when the engine is cold, and runs the electric AC in an economy mode to improve gas mileage.
If you set the defroster on, or the temp to MIN or MAX, ECO is disabled.