I have a 2011 MB with a dome light problem. This is the basic light with auto/off/on position. The light does not operate the the auto position. Switch contacts are ok. All rear cargo lights work properly. Manual position works properly. The dash indicator shows when either door is opened, but no light. I show about 12v on the auto side and a full volt higher on the manual side of switch. Dealer said the SAM shows the circuit has been shut down because of short. I haven't found a short yet and I have pulled the A-pillar cover and also looked under dash and above headliner (as much as possible without pulling it), and all looks ok. Any thoughts? Where is the BCM located? Does anyone have a lighting diagram for this? I was thinking of just running new wiring for the dome from the BCM.