RH Side computer Box in trunk i pput a used one in car cause previous one was shot i didnt get no power now i get the power all lights work but at night the lights arent on im guessin the running lights?? But!!
could it be A fuse.... also it was sittin for a while since i didnt have lights i hadd to get a jump but battery gauge in dash was below low when i hit gas lights would brighten up i let go they dim then it ended up cutting off plus my airbag light came on i just dont understand why my lights work but not the running lights please HELP!!!

 

What year XJ6 are we looking at here. I might be able to help. Let me know and we can take things from there.