Hello and welcome.
When this light comes on the dash, it means that the tranfercase control module for the All Wheel Drive has detected a problem.
You would need to get that module scanned for trouble codes. These codes give an indication as to what part of the system has a problem.
The problem could any number of sensors, a problem with the encoder motor, a faulty module itself, or just needs a software update.
No way to tell without getting the computer scanned for codes.
Without a scanner, about the only thing you can do yourself is to check the ATC fuse #8 in the underhood fuse block.