Case IH 520624-02 - ACM – ACM: Second function switch A circuit fault

Electrical circuit failure (such as a short to ground, open circuit, or out-of-range voltage) originating from the secondary function 'A' switch, which is located on the tractor's Multi-Function Handle (joystick).

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series (Wheeled and Rowtrac)
• Case IH Steiger AFS Connect Series
• Case IH Quadtrac AFS Connect Series

1. 1

   Check ACM Power and Ground: Verify the unswitched power input (Pin 1 - UNSW B+), switched power input (Pin 2 - SWB+), and ground (Pin 7 - GND) at the ACM harness.

2. 2

   Inspect the Multi-Function Handle (MFH) Harness: Check the wiring harness routing from the joystick down through the armrest to the ACM for pinch points, chafed wires, or stretched connections.

3. 3

   Connector Pin Inspection: Disconnect the MFH harness from the ACM and inspect the pins for corrosion, pushed-back pins, or debris.

4. 4

   EST Monitoring: Connect the Case IH Electronic Service Tool (EST) to the CAN1/ISOBUS diagnostic connector. Navigate to the ACM configuration and monitor the live state of 'Second function switch A' while physically pressing the button to see if the signal flickers or remains dead.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical spikes while working on the CAN bus modules.

2. 2

   Access the Armrest Internals

   Remove the protective plastic shrouding around the AFS Connect Multicontroller armrest to expose the ACM and the base of the Multi-Function Handle.

3. 3

   Test the Switch Circuit

   Disconnect the joystick harness. Using a multimeter, perform a continuity test on the pins corresponding to the Second Function Switch A while actuating the button.

4. 4

   Isolate the Failure

   If the switch does not show continuity when pressed, the internal microswitch in the Multi-Function Handle has failed. The handle assembly will need to be replaced. If the switch tests fine, perform a continuity test on the wiring harness between the joystick connector and the ACM. Repair any broken wires.

5. 5

   Reassembly

   Plug all connections back in securely, ensuring the harness is routed away from the armrest pivot points.

6. 6

   Clear Codes

   Reconnect the battery, turn the key on, and use the EST to clear the 520624-02 fault code. Actuate the switch multiple times to ensure the code does not return.