That is correct.
The module to the left of the radio in 2001~2003 is the Generic Electronic Module which controls various timing and other body module functions. In these years, it does not control the transfer case.
The Electronic Shift Control is done by the 4x4 Module and it is under the passenger side kick panel in 2001~2003. The controls or their wiring occasionally act up but the main cause of Ranger 4WD problems is the Shift Motor/Encoder assembly down on the transfer case.