Case IH 3597-06 - BCM – BCM: LIN actuator switched power - short circuit to ground

The switched power supply circuit feeding a LIN (Local Interconnect Network) actuator is shorted to ground. The voltage supply wire from the control module to the actuator is making unintended contact with a ground source, causing the module to detect excessive current draw or voltage drop and disable the circuit.

• MAGNUM AFS Connect
• Magnum 400 AFS Connect

1. 1

   Inspect the BCM power supply fuses in the cab fuse panel for a blown fuse caused by a dead short to ground.

2. 2

   Visually inspect the wiring harness running from the BCM to the HVAC LIN actuators for pinched wires, chafing against metal brackets, or melted insulation.

3. 3

   Disconnect the electrical connector at the LIN actuator and measure resistance between the switched power pin and a known good chassis ground to isolate if the short is in the harness or internal to the actuator.

4. 4

   Verify that the BCM pin for the LIN switched power is not internally shorted by testing the pin directly at the BCM connector.

1. 1

   Disconnect Power

   Turn off the key switch and disconnect the negative battery cable before performing electrical repairs.

2. 2

   Address the Short

   If the harness is shorted: Locate the chafed or damaged section of the wire and repair it using OEM-approved heat-shrink butt connectors, or replace that section of the cab harness, wrapping the repaired section in anti-chafing loom. If the actuator is shorted: Remove the mounting screws securing the faulty LIN actuator to the HVAC housing and install a new actuator.

3. 3

   Replace Fuses

   Replace any blown BCM fuses with one of the exact same amperage rating.

4. 4

   Reassemble and Calibrate

   Reconnect the battery, turn the key to the ON position, use the EST (Electronic Service Tool) to clear the inactive 3597-06 code from the BCM, and run an HVAC actuator calibration routine so the BCM can learn the end-stops of the new actuator.