Are you sure you checked all the doors and closed them?
Do you have a DVOM and are you ready to start checking each switch?
All 4 door switches checked out ok. I could not locate the trunk switch, I'd likely have to remove some plastic covers.
Two other clues:
The light on the driver door (the one that only turns on when the door is open) does not work (bulb good). The one on the passenger side works normally.
After replacing the fuse, I smelled an electrical smell.
I'm thinking it is not the rear hatch switch. Is there some kind of relay or brain that is tied into the door light circuit?
Here is the schematic to your Sienna and the interior light.....
If you smelled something electrical, that's not good.
The body ECU's have not been a pattern failure problem but I have replaced a few and yes in this case, it does control the interior light. I have included the all pages for this schematic and I hope this helps. The part number might be stamped on the ecu or just a quick call to your local Toyota Dealer and they can give it too you. Thank you again,