So I’ve had an Intermittent issue and I’ve searched the forums and found nothing.

2008 ram 3500 dually cummins

driving down the road at speed 4lo light blinks and sounds like the t case grinds. I have already disconnected it. I replaced the motor and the switch this past weekend. Still did it to me this morning. Does the switch run to a module before going to the motor? I’m not sure what to do now except go through all the wiring. Tia