Hello, and welcome to JA!! the most common problem for this concern, is the transfer case module not waking up. here is some info on this concern. try pulling the fuse that the provided info states. but normally requires the transfer case module to be replaced and programmed with the latest software.
If there is anything you dont understand, Please fell free to ask me to explain!!
Some customers may comment that the 4WD/AWD indicator lights on the selector switch do not work, or the 4WD/AWD system may be inoperative and/or the service 4WD light is illuminated. The condition is typically intermittent and always occurs at key-up. Upon investigation, the technician may find DTC C0550 set.
The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode".
When the TCCM is in the "sleep mode", it will not communicate with the class II bus or the Tech 2®.
Important: For the 2002 model year, the TCCM must be replaced and reprogrammed.