i guess you mean a rear for lamp bulb, i have a 3 series 'n' regd 1995. open your boot and remove the light cluster surround, look for the bulb holder which should be at the bottom farthest from you, twist the holder 45 degrees to release the assy with the bulb still in it. replace bulb which is a baynet fitting and replace back into cluster.
matt busby, January 2008
