Case IH 520627-02 - ACM – ACM: Second function switch B circuit fault

This fault code indicates an electrical circuit malfunction associated with the "Second function switch B". The system has detected an abnormal voltage, open circuit, or short (to ground or power) in the circuit connecting this switch to the control module.

• MAGNUM AFS Connect
• Steiger AFS Connect
• Puma AFS Connect

1. 1

   Inspect the Multicontroller joystick 'Second function switch B' button for physical damage, sticking, or debris lodged around the button housing.

2. 2

   Remove the armrest trim panels and inspect the wiring harness between the Multicontroller joystick and the Armrest Control Module (ACM) for chafed wires, pinch points, or disconnected plugs.

3. 3

   Disconnect the harness at the ACM and the Multicontroller to check for bent, pushed-back, or corroded pins.

4. 4

   Using a multimeter, test the switch circuit for continuity. Verify that the switch state changes cleanly when pressed and released, and ensure there is no short to ground in the signal wire.

5. 5

   Connect the Case IH EST diagnostic tool and monitor the live data for the Armrest Control Module to see if the switch input changes when physically pressed, confirming if the ACM is receiving the signal.

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery cable to prevent electrical shorts during repair.

2. 2

   Access the Components

   Remove the retaining screws on the armrest console casing to expose the internal Armrest Control Module (ACM) and the base of the Multicontroller joystick.

3. 3

   Isolate the Fault

   If the wiring harness is damaged (e.g., a broken wire), repair the wire using OEM-approved splicing techniques or replace the armrest sub-harness. If the switch itself fails the continuity test, the Multicontroller handle assembly must be replaced. If the switch and wiring test perfectly but the ACM fails to read the input, the ACM itself may have a failed internal driver.

4. 4

   Component Replacement

   Swap out the faulty Multicontroller handle or ACM. Ensure all multi-pin connectors are seated firmly and locked into place.

5. 5

   Reassembly

   Reinstall the armrest console casing and trim panels.

6. 6

   Calibration and Clearing

   Reconnect the battery. Turn the key to the ON position. Use the tractor's display or the EST tool to clear the inactive 520627-02 fault code. Test the second function switch to ensure normal operation.