Had this exact problem. Mine actually caused the battery to die a couple of times before I realized that the light was the problem.

Either way, it took 4 visits to the dealership for them to resolve it. But before they did, they replaced the PCM module 4 times, the entire dome light twice and goodness knows what else at great expense to DM.

Of course, after 3 months of this they finally figured out it was the switch in the trunk!

Long letter to DM entailed as I complained about an obvious lack of training on the dealerships part. Coupled with the myriad of other problems (mostly quality related things, rattles, wind noise etc..) that led to a lengthy complaint letter to DM.

So, my point being, is you might want to check the simple things, the doors and the trunk to make sure that's not the problem first.

Good luck!