Tailgate opening question

[mcgyvah]

My vehicle is a 2006 model l320 2.7 sport , just the basic model, manual tailgate.
On the rear tail gate there are 2 switches, one is above the number plate, the other is a round switch lower down to the RHS.
It is my understanding that the one above the number plate should open the top "window" half. and the round one lower down should open the entire thing??

On mine, the top switch opens the entire thing, the bottom switch does nothing.
I would like to be able to open the top piece, however, all the 'how to's" i can find say that if the top doesn't open, its usually the top switch that is faulty.
but as I said, pushing the top switch unlatches the entire tailgate for me, the top switch clearly works and the bottom switch clearly doesnt do anything.
Also of note is that holding the unlock on dash, or, on the remote, just unlocks the entire thing.

I would appreciate if someone could explain what i am looking at here. as it seems arse about.
Thanks

[haydent]

lower round for tailgate higher near number plate for glass only.

I did have this problem after trailing options in GAP CCF Rear glass door will only open when main boot is open ?