From my service manual for HDKAJ, HDKAK, HDKAT:
GOVERNOR ACTUATOR FAULT—CODE NO. 19
(Controller sensed open or short circuit)
1. Remove the front housing panel (p. 6-4) and reconnect the engine wiring harness connectors E1-1 and E1-2 to the governor actuator if they are loose. Polarity does not matter (p. 19-1, 13-1).
2. Measure actuator coil resistance with a digital ohmmeter. Replace the actuator stator assembly if coil resistance is not 1.7 to 2.8 ohms.
3. Disconnect engine harness connector P1 from the controller assembly (p. 19-1, 19-4). Check for electrical continuity between pin P1-1 and quick connector E1-1 and between E1-2 and ground. Replace the engine harness if either leg lacks electrical continuity. Also check for missing, bent or corroded terminals and connector pins and repair or reconnect as necessary.