The mode shifter has turned out to be one of the common-fail parts on this washer and it's regular rolling inventory for me. Although the fault/error codes will point specifically to the mode shifter if there's a problem with it, there may be situations where you want to test the mode shifter directly. Brother Eric calls the dance steps on that little ditty:
Yes, you should have 5vdc at J2 pin 2 (pink) with connector disconnected. This is a digital logic level provided via pull-up resistor on the control board. The rpm sensor in the shifter will "pull" this level low (0 volts) each time the optical sensor light path is interrupted by the rotating blade inside the transmission. This creates a digital square wave to the processor (switches between 5vdc and 0vdc). The frequency of the square wave is dependent upon speed of rotation of the transmission and is calclulated by the processor to determine rpm. If you monitor J2 pin 2 while wire harness is connected and rotate the tub very slowly, you should see it switch between 5vdc and 0vdc. You should also have 5vdc on J2 pin 1 when in spin mode and 0vdc when in agitate mode.
Source: Amana NTW4600yq