First, you should have the vehicle scanned. I wouldn't rule out the module as the problem.
Illumination of the Lamp indicates a problem with the drive system.
There will probably be a Transfer Case Code set to aid in diagnostics.
The only way to get the light to go off is to clear Transfer Case codes.
This light can NOT be shut off or reset any other way.
Transfer Case codes should be read and repaired before clearing them.
The diagnostic trouble codes are displayed on the three transfer case shift select buttons. The shift select buttons are located to the right of the instrument panel cluster. When pin 13 of the data link connector is grounded and the ignition switch has been in the OFF position for at least five seconds prior to positioning the ignition switch to the RUN position, the shift select buttons will blink a number of times in order to indicate a diagnostic trouble code from 1 to 4.
1.1. Position the ignition switch to OFF.
Ensure the ignition switch is positioned to OFF for at least 5 seconds.
1.2. Connect pin 13 (see this page http://www.troublecodes.net/OBD2) on the data link connector to a vehicle ground source.
The data link connector is located in the cab under the instrument panel on the drivers side.
1.3. Position the ignition switch to RUN.
1.4. Note the shift select buttons for blinking codes.
If the shift select buttons all blink one time and stop, and do not continue to blink, no fault codes are stored in the TCCM.
The transfer case shift select buttons will blink in order to identify any stored DTC. If only one code is stored in the TCCM memory, that code will blink repeatedly with a three second delay between blinking sequences. If more than one code is stored, the first code will blink once, then after a three seconds delay, the next code will blink. This sequence will continue until pin 13 is no longer grounded.
When reading the diagnostic trouble codes, the number of shift select buttons blinks will indicate the code number.
Important: The codes will not clear if the 15-amp 4WD fuse is not removed for at least 30 seconds.
The code 1 will continue to occur until the ignition switch is cycled from RUN to OFF five times.
Perform the following in order to clear the Diagnostic Trouble Codes (DTC) and in order to clear the stored memory from the Transfer Case Control Module (TCCM) .
Turn the ignition switch to the OFF position.
Remove the 15-amp 4WD fuse.
Wait at least 40 seconds then replace the fuse.
Cycle the ignition switch from RUN to OFF five times in order to clear the diagnostic trouble code 1 from the TCCM.
Let us know if there are any trouble codes.