hehehehe, Sorry I don't mean to laugh, but...
Check you rear interior light switch, I bet it's on. Should be the last rocker switch on the right side of the console. I just went out and check function on mine, and yes all the rear lights come on including the door lights.
Again, sorry for laughing, but...sometimes it's the simple things.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.