Case IH 518666-06 - ACM – ACM: Mouse wheel voltage low

The voltage signal coming from the MultiControl Armrest's encoder dial (referred to as the "mouse" or EDC mouse) has dropped below the acceptable lower limit.

• MAGNUM AFS Connect
• Steiger / Quadtrac AFS Connect
• Optum AFS Connect
• Puma AFS Connect

1. 1

   Open the armrest console and inspect the wiring harness connecting the encoder dial to the ACM for pinched wires, chafing, or loose connections.

2. 2

   Disconnect the harness at the encoder dial and the ACM to check for bent, corroded, or pushed-out pins.

3. 3

   Turn the key switch to the ACC position and measure the reference voltage supplied by the ACM to the encoder dial. If missing or extremely low, the issue may be the wiring harness or the ACM itself.

4. 4

   If reference voltage is present, measure the signal return wire while turning and pressing the encoder dial. If the voltage remains stuck low and does not change, the encoder dial has failed internally.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical shorts.

2. 2

   Access the Armrest

   Remove the retaining screws on the MultiControl Armrest housing to lift the top cover and access the internal components.

3. 3

   Disconnect the Encoder

   Locate the encoder dial (mouse) assembly. Unplug its electrical connector from the armrest wiring harness.

4. 4

   Replace the Component

   If the encoder was diagnosed as faulty, remove the mounting screws holding the dial assembly to the armrest bezel and install the new encoder dial.

5. 5

   Reassembly

   Reconnect the electrical harness, ensuring the connector clicks securely into place. Reinstall the armrest cover and tighten the screws.

6. 6

   Calibration/Clearing

   Reconnect the battery and turn the key on. Connect the Case IH EST (Electronic Service Tool) to the diagnostic port. Clear the 518666-06 fault code. You may need to navigate to the ACM configuration menu in the EST to verify the encoder dial is recognized and functioning.