Why would I have N and D on shift indicator and nothing else?

Is the check engine light on, and are there any other symptoms? The "PRNDL" is operated by the instrument cluster based on information that comes across the data bus from the transmission control module, or the fuel injection control module based on the switch inputs from the range selector switch. A tech needs to check the operation of that switch assembly as well as use the scan tool to test the PRNDL operation to diagnose this issue.