That's it. It's been doing it for about 3 weeks. At first it was intermittent but now it's on All. The. Time.
Kind of annoying really, especially driving at night. The interior lights operate normally so I'm assuming it's not a switch problem, although I wouldn't put it past the GM electrical engineers of the day to have multiple switches for that.
Both doors are closed. I checked that first. Twice. Both of them.
I've been poking through the FSMs and I can't find any reference to it. Maybe I'm looking for the wrong thing? "Door Ajar" Lamp? Door Warning Indicator? Hey Stupid Close Your Door Light?
FWIW, while trying to fix this problem by being lazy, I sprayed some electrical contact cleaner into both of my door latch mechanisms to possibly free up a stuck switch, and I have noticed that the totally random RAP has gone away and operates normally.