Case IH 520606-02 - ACM – ACM: Rear hitch lower switch circuit fault

The Failure Mode Identifier (FMI) "02" indicates that the signal from the rear hitch lower switch is erratic, intermittent, or incorrect. The controller is receiving a voltage or resistance value that falls outside the expected normal operating range for this switch, or the signal is dropping out unexpectedly.

• MAGNUM AFS Connect
• Magnum 180 AFS Connect
• Magnum 200 AFS Connect
• Magnum 240 AFS Connect
• Magnum 250 AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Inspect the rear hitch lower switch on the MultiControl Armrest for physical damage, sticking, or debris preventing full travel.

2. 2

   Access the wiring beneath the armrest console. Inspect the connector at the switch and the main 17-pin connector at the ACM for loose pins, corrosion, or pushed-back terminals.

3. 3

   Connect the Case IH Electronic Service Tool (EST). Navigate to the ACM advanced configuration (Parameter: Config B/b 3.7 Rear hitch lower switch). Monitor the live data state while toggling the switch to see if the signal drops out or registers erratically.

4. 4

   Disconnect the switch and use a multimeter to test for continuity across the switch contacts while pressing it. If the switch tests good, check the wiring harness for a short to ground, short to power, or an open circuit between the switch and the ACM.

5. 5

   Look for companion codes (such as 520608-02 for the rear hitch raise switch). If both are present, it highly suggests a shared ground failure or a damaged common wiring harness rather than a failed switch.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Switch

   Carefully remove the trim panels on the AFS Connect armrest to expose the internal switch modules and wiring.

3. 3

   Component Isolation

   Disconnect the electrical pigtail from the rear hitch lower switch.

4. 4

   Replace or Repair

   If the switch failed the continuity test: Remove the retaining clips/screws holding the switch or joystick pod in place and install the replacement unit. If the wiring is damaged: Repair the chafed wire or replace the damaged connector pin using an approved OEM terminal repair kit.

5. 5

   Reassembly

   Reconnect the switch pigtail and reinstall the armrest trim panels.

6. 6

   Calibration & Clearing

   Reconnect the battery. Turn the key on and use the Case IH EST to clear the inactive 520606-02 fault code. Test the rear hitch lower function to ensure the code does not return and the hitch operates smoothly.