On my relatively new [9 months],I have noticed an Orange colored electrical line on the inside of the hood. At the end of the line , 12" to 14" there appears to be either a small light or a mercury switch. Any ideas to what purpose this device serves.
Thanks!!

 

Orange lines are high voltage in hybrid vehicles, I wouldn't mess with it, as you could electrocute yourself. Mercury switches are commonly used to determine vehicle angle. ABS units typically use one to know if the vehicle is diving forward while braking. Another common use is an under hood light, where when the hood opens, the mercury will complete the circuit.