Rear tail light question

[13Jester13]

Just installed my new LED tail lights and saw there is a predetermined spot on the tail gate section of the tail lights below the reverse lights. On the stock ones, the spot is there but no setup for a bulb. On the new ones, there is a socket to hold a bulb, but did not work with any other light (ie brakes, turn, etc...) Anyone have any idea what the heck this light does, and better yet best way to make it work without shorting something out Thanks!

Old ugly orange tail lights (Blue arrow obviously points to where I am talking about)



New Euro style LED tail lights. So much better with no orange on the X!



Also have some Solaris bulbs coming because I cannot stand that orange reflection. Its the little things that count