Hello,
I installed on my Golf MK7 the same model of aftermarket taillights that JR14 installed on his car. I notice in the images on EBAY that the connections are identical to mine. In the picture on site vland-official.com the connections are different from those on EBAY. You must connect the yellow cables between the left and right taillights correctly. I am convinced that you do not need a new wiring or coding. This video can help you review how cables are connected.
At 2:22 the cables can be seen in the box. It's something with yellow plugs in the bag.
The yellow cables you received will need to be installed in the same way as they are installed in this video. JR14 installed another type of cable because it upgraded from halogen taillights to LED taillights.
If it still doesn't work then you have to do coding and adapter harness. Unlike cars in europe all mk7 Golf models in North America need coding and adapter harness.
OBDEleven coding
1/ Select Central Electrics
2/ Select Security Access
Enter in the code - 31347
3/ Select Adaptation
(1)-Leuchte20BR LA71-Lasttyp 20 - New Value - 34 – LED Bremsleuchten
(5)-Leuchte20BR LA71-Lichtfunktion B 20 - New Value - not active
(8)-Leuchte20BR LA71-Lichtfunktion C 20 - New Value - not active
(1)-Leuchte21BR RC8-Lasttyp 21 - New Value - 34 – LED Bremsleuchten
(5)-Leuchte21BR RC8-Lichtfunktion B 21 – New Value - not active
(8)-Leuchte21BR RC8-Lichtfunktion C21 - New Value - not active
(1)-Leuchte23SL HLC10-Lasttyp23 - 33 – New Value - LED-Modul Blinkleuchten
(4)-Leuchte23SL HLC10-Lichtfunktion A 23 - New Value - not active
(8)-Leuchte23SL HLC10-Lichtfunktion C 23 - New Value - Blinken links Hellaphase
(10)-Leuchte23SL HLC10-Dimmwert CD 23 - New Value – 127
(1)-Leuchte24SL HRA65-Lasttyp 24 - New Value – 33 – LED-Modul Blinkleuchten
(4)-Leuchte24SL HRA65-Lichtfunktion A24 - New Value - not active
(8)-Leuchte24 SL HRA65-Lichtfunktion C 24 - New Value - Blinken rechts Hellaphase
(10)-Leuchte24SL HRA65-Dimmwert CD 24 - New Value – 127
(1)-Leuchte27NSL RC6-Lasttyp 27 - New Value - not active.