When mine was out, it turned out that it was the switch in the latch.

 

So your car did not notify you that your engine lid was open when driving when your switch was broken? That's interesting then because the diagrams I have access to show only one ground shorting microswitch for the rear hood. It feeds into the rear control unit so I'd assume it directly controls the light as well as sending a signal to the on board computer network module that the rear hood is open.

 

I had no warning messages or lights.