Not to ask a stupid question, but have you checked the lighting thumbwheel to be sure it isn't set to "DOME ON"?
If the thumbwheel is set correctly, are you getting any "open door" indicators? If not, you may have a bad BCM. You might want to download the free demo version of AlfaOBD, pick up a cheap Bluetooth OBD module and use the "test" mode to see if you can toggle the interior lamps on and off manually. There may also be a BCM DTC stored, which AlfaOBD can read for you.