My left tail light is out. so I went and bought new bulb's changed all four bulbs left n right. my left still wont come on. so I swapped the bulb holders left to right and they both work. but i can reassemble cause left wont fit where the right bulb holder goes. so i swapped holders again right to left and my left holder wont work on left side. idk the problem if the left holder works on right side. any suggestions?

bad wiring, or bad holders, get new asap

get a test light

test the wires

find one that isn't working right

trace it until you find the problem

fix problem

become another vw owner with a stereotypical "vw wiring sucks" problem.