CT32150 Auto-Eco Mode - No icon light turns on

For the CT32150, the Instruction Manuals state that when pressing the "+ or -" the unit will go into Auto-Eco mode and the Auto-Eco mode icon will turn on. This is correct, that when you press the + or - the unit automatically goes into Auto-Eco mode.  There is no indicator light, as the unit automatically goes into Auto-Eco model when the + or - button are pressed.