Case IH 18330 (4166.02, 4166.03, 4166.04, 518663.07) - ACML – ACML: MFH Rear Hitch Fast Lower Switch (S117) Error

The controller is receiving an invalid, continuous, or missing electrical signal from the button used to quickly lower the rear 3-point hitch, indicating a short to high source, short to ground, or erratic/intermittent data.

• MAXXUM T4E
• VESTRUM CVX
• Case IH Puma
• Case IH Magnum
• Case IH Steiger
• Case IH Optum

1. 1

   Inspect the Rear Hitch Fast Lower button on the Multi-Function Handle. Check if the button is physically stuck, jammed with dirt/debris, or damaged.

2. 2

   Locate Connector X846 inside the armrest and inspect it for backed-out pins, corrosion, or loose connections.

3. 3

   Using a multimeter, check the wiring between the MFH and the ACML for continuity. Verify that there is no short to ground or short to 12V power on the hitch lower switch circuit.

4. 4

   Use the AFS Pro display (or Pro 1200 monitor) to view the 'Faults and Warnings' menu. Check if the code is 'Active' or 'Inactive'. If inactive, attempt to clear it and see if it returns upon pressing the switch.

1. 1

   Disconnect power

   Disconnect the earth cables at the battery before working on the armrest electronics to prevent damage to the electronic and electrical systems.

2. 2

   Access armrest internals

   Remove the retaining screws on the armrest control cover to expose the base of the Multi-Function Handle and the internal wiring harness.

3. 3

   Disconnect the MFH

   Unplug Connector X846 (and any secondary connectors like X850 or X858 depending on options) from the Armrest Control Unit.

4. 4

   Remove the handle

   Unbolt the Multi-Function Handle assembly from its mounting bracket. Because the S117 switch is integrated into the handle's circuit board, the entire handle assembly must be replaced.

5. 5

   Install new part

   Mount the replacement Multi-Function Handle to the bracket.

6. 6

   Reconnect wiring

   Plug Connector X846 back into the ACML, ensuring the locking tab clicks into place. Route the wiring harness carefully so it does not pinch when the armrest is closed.

7. 7

   Reassemble and test

   Reinstall the armrest cover, reconnect the battery, and turn the ignition on. Navigate to the display monitor to clear any stored fault codes, then test the rear hitch fast lower function to confirm the repair.