Operation Description from the FCM

The Front Control Module (FCM) utilizes the input from the transfer case mounted mode sensor, the instrument panel mounted selector switch, and the following information from the vehicle's CAN bus to determine if a shift is allowed.

Engine RPM and Vehicle Speed
Diagnostic Requests
Manual Transmission Clutch Switch
Brake Applied
PRNDL
Ignition Status
ABS Messages
Once the FCM determines that a requested shift is allowed, it actuates the bi-directional shift motor as necessary to achieve the desired transfer case operating mode. The FCM also monitors the mode sensor while controlling the shift motor to determine the status of the shift attempt.

Not much of anything is hard wired anymore.