Originally Posted by supernova1
Here is how it works for me (my car uses two-stage door unlock):
After your car sits closed for several hours
1. Press "Open" on the key fob once - the driver door opens, but dome light is OFF;
2. Press "Close" on the key fob once - the driver door closes;
3. Press "Open" on the key fob once - the driver door opens and the dome light is ON.
I believe that it is a "stealth" feature in case you want to open your car, but do not want to attract attention to it (you figure the case for this), so it has a mode when the dome light is OFF on the first "Open" click.
It also seems to me that this feature has a timer - if you close your car doors and then after several minutes press "Open" again, the dome light will light up. Only after the car sits closed for several hours (can not get the exact time) the dome light is OFF on the first "Open" click.
I can not still figure out the dome light switch with "OFF" sign - to me it just toggles through two states (switch backlight ON/OFF), but does not do anything other than this.
Kudos to Supernova1 for figuring this out. You'd think it could be explained in the owner's manual easily enough. I was going crazy trying to figure out when and why it turned on or not.