Case IH 518724-02 - ACM – ACM: Rear hitch lower rate switch circuit fault

The system has detected an electrical anomaly (such as an open circuit, short to ground, short to power, or out-of-range voltage) in the circuit of the switch or potentiometer that controls the drop/lower speed rate of the rear 3-point hitch.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series (Models 180, 200, 220, 240, 250, 280, 310, 340, 380, 400)
• Case IH Steiger / Quadtrac / Rowtrac AFS Connect Series (Models 350 through 600)

1. 1

   Inspect the physical condition of the rear hitch lower rate dial/switch on the armrest for physical damage, sticking, or liquid spills.

2. 2

   Access the underside of the armrest control panel and inspect the wiring harness and connector going to the hitch lower rate switch for chafing, pinched wires, or loose/corroded pins.

3. 3

   Using a multimeter, verify the 5-volt reference signal, ground, and signal return from the switch to the ACM.

4. 4

   Connect the Case IH Electronic Service Tool (EST), navigate to the ACM live data, and monitor the voltage/percentage of the rear hitch lower rate switch. The value should change smoothly without dropping out or spiking as you move the switch.

5. 5

   Look for other ACM codes (e.g., 518725-02 for the raise rate switch, or CAN bus communication errors like 2818) which may point to a shared ground/5V reference issue or a failing ACM.

1. 1

   Preparation

   Park the tractor on a level surface, lower the rear hitch completely (if possible), turn off the engine, apply the parking brake, and disconnect the battery to prevent electrical shorts.

2. 2

   Access the Armrest Internals

   Carefully remove the retaining screws and trim panels on the operator's armrest console to expose the internal switch modules and the ACM.

3. 3

   Isolate the Component

   Disconnect the electrical pigtail from the rear hitch lower rate switch.

4. 4

   Replace the Switch/Wiring

   If the switch failed the multimeter/EST sweep test, remove its retaining clips/screws and install a new switch. If the wiring is damaged, repair the affected section of the armrest sub-harness using OEM-approved connectors.

5. 5

   ACM Replacement (If Necessary)

   If the switch and wiring test perfectly but the ACM is not reading the input, the ACM itself may have an internal fault. Disconnect the 17-pin connectors and swap the ACM. (Note: A new ACM will require flashing/configuration using the EST to match the tractor's specific EHR and joystick layout).

6. 6

   Reassembly & Calibration

   Reconnect all harnesses, reinstall the armrest covers, and reconnect the battery.

7. 7

   Clear Codes

   Turn the ignition on, use the EST or the AFS Pro display to clear the 518724-02 fault code, and test the rear hitch drop rate functionality to verify the repair.