Case IH 2385-02 - ACM – ACM: Rotating beacon light command switch circuit fault

The "-02" Failure Mode Indicator (FMI) typically indicates erratic, intermittent, or incorrect data, which usually points to an open circuit, a short to ground, or a short to power within the switch's wiring circuit.

• MAGNUM AFS Connect
• Magnum 250
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400
• Steiger AFS Connect
• Optum AFS Connect

1. 1

   Inspect the physical rotating beacon light switch for physical damage, sticking, or liquid intrusion

2. 2

   Access the back of the switch and inspect the wiring harness connecting the switch to the Armrest Control Module (ACM) for chafed wires, pinched harnesses, or disconnected/corroded pins

3. 3

   Use a multimeter to test the switch's continuity to verify that the switch properly opens and closes the circuit when toggled

4. 4

   Check the voltage at the switch connector to ensure the ACM is sending the correct reference voltage, and test the ground circuit for high resistance

5. 5

   Verify that no fuses related to the cab lighting or beacon circuit have blown

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical shorts during repair.

2. 2

   Access the Switch

   Carefully pry up or unscrew the armrest control panel cover (or the respective cab trim panel where the beacon switch is mounted) to access the switch wiring.

3. 3

   Disconnect and Inspect

   Unplug the electrical connector from the back of the beacon light switch. Inspect the connector terminals for pushed-out pins, corrosion, or melting. Clean with contact cleaner if necessary.

4. 4

   Test or Replace the Switch

   If the switch failed the continuity test during diagnostics, push the retaining tabs on the side of the switch body to pop it out of the bezel. Snap the new OEM replacement switch into place.

5. 5

   Repair Wiring (If Applicable)

   If the switch tested fine, trace the wiring harness back to the ACM. Repair any broken or shorted wires using proper automotive-grade splice connectors and heat shrink.

6. 6

   Reassembly

   Reconnect the switch harness and reinstall the armrest/cab trim panels.

7. 7

   Clear Codes and Test

   Reconnect the battery. Turn the key on and use the AFS Pro display (or a diagnostic service tool) to clear the inactive 2385-02 fault code. Toggle the beacon light switch to verify the rotating beacon operates correctly and the code does not return.