Case IH 518665-02 - ACM – ACM (Armrest Control Module): Mouse draft switch circuit fault

Indicates an electrical circuit failure—such as an open circuit, short to ground, or voltage out of range—in the draft control switch/potentiometer located on the MultiControl Armrest "mouse" (the electrohydraulic hitch control pod).

• MAGNUM AFS Connect
• Magnum AFS Connect Series
• Magnum 250 AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect
• Steiger AFS Connect

1. 1

   Visually inspect the wiring harness leading to the EDC (Electronic Draft Control) mouse under the right-hand console/armrest covers for pinched wires, chafing, or rodent damage.

2. 2

   Verify that the switch is receiving a 5V or 12V reference voltage (depending on the specific pinout) and has a solid ground. Check the fuses related to the hitch controller and armrest.

3. 3

   Use the Case IH Electronic Service Tool (EST) or the tractor's AFS Pro display diagnostic menu to monitor the live voltage of the rear hitch draft control potentiometer. Look for voltages that are stuck too high or too low.

4. 4

   Disconnect the harness at the EDC mouse and the ACM. Check for corroded, backed-out, or bent pins.

1. 1

   Power Down

   Turn off the tractor key and disconnect the battery ground to prevent electrical spikes.

2. 2

   Access the Armrest

   Remove the trim panels on the right-hand MultiControl Armrest to access the underside of the hitch control pod (the "mouse") and the ACM.

3. 3

   Test the Harness

   Perform a continuity test on the wires running between the draft switch connector and the ACM connector. If there is a break or a short to ground in the harness, repair the damaged wire.

4. 4

   Replace the Component

   If the wiring harness tests good, the internal potentiometer/switch inside the EDC mouse has failed. Remove the retaining screws for the hitch control pod and replace the draft switch or the entire mouse assembly.

5. 5

   Reassemble and Power Up

   Reconnect all electrical plugs, reinstall the armrest trim, and reconnect the battery.

6. 6

   Calibration

   Turn the key on. Use the EST or the tractor's display to clear the inactive 518665-02 fault code. You must perform a hitch controller calibration so the ACM can learn the minimum and maximum voltage values of the new draft switch.