I'll crawl under there and give that a try this morning sometime. I've checked everything else, so it is most likely the t-case switches, but I want to be sure before I go throw money at it.

On a related note, it looks like the switches are on top of the t-case and difficult to get to. Is this the sort of thing where I can remove the rear driveshaft, remove the t-case crossmember and lower the case enough to get the switches in and out?