Mike, thanks for the info.

I've read a little about the transfer case gear issue, and a notable symptom seems to be a clicking noise from the transfer case actuator, which is not present for me. At this point, it seems as though removal and inspection of the actuator to rule it out will be easier than finding a proper pinout for the ABS module harness to rule out wheel speed sensors first.

If your sig is current, I'm actually in Neenah, WI - awesome!