I just bought a brand new Highlander Hybrid 4WD last Monday. There's a red button mounted on the dash where the 115V AC main switch would normally be (according to the manual -- I did RTFM BTW ). It looks like a cheap button you could get at Radio Shack and it lights red when I push it while the vehicle is in operation. There is no mention of it in the owners manual, the salesman was clueless (surprised? I knew more about the vehicle than he did and I wasn't even shopping for one) and it is unlabelled.

What does it do? Only thing I could think of is 4WD selector?