LED Tail light/ turn signal out

Hi all. My right rear LED turn signal on my 04 M3 Vert went out and I would like to know if I have to purchase new tail lights or could it be something else? Also, how much would it cost and would I have to purchase a pair or can I just order the right rear turn signal/tail light? Thanks in advance!

You have to replace the whole light. About 170 each side from the dealer. They cannot be repaired because they are sealed units