Case IH 517675-02 - ACM – ACM: Auto guidance switch circuit fault

The control module has detected an electrical anomaly—such as an open circuit, short to ground, or short to power—in the circuit responsible for the auto guidance engage switch.

• MAGNUM AFS Connect
• Magnum AFS Connect Series (Models 180, 200, 220, 240, 250, 280, 310, 340, 380, and 400)
• Optum AFS Connect Series (Models 250, 270, 300)
• Steiger & Quadtrac AFS Connect Series
• Maxxum Series (Tier 4B / Stage V models equipped with the MultiControl Armrest)

1. 1

   Check for related codes using the AFS Pro 1200 display or Electronic Service Tool (EST) to identify broader harness issues or module communication loss.

2. 2

   Inspect the wiring harness connecting the Auto Guidance Switch to the Armrest Control Module (ACM) for chafing, breaks, or pinched wires inside the armrest console.

3. 3

   Ensure the connectors at both the switch and the ACM are fully seated and inspect pins for damage, push-back, or corrosion.

4. 4

   Use a multimeter to test the auto guidance switch for proper continuity when pressed and released.

5. 5

   Check the switch circuit for a short to ground or short to power.

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before performing electrical repairs on the tractor to prevent short circuits or module damage.

2. 2

   Access the Switch

   Carefully remove the necessary trim panels on the Multicontroller armrest to access the underside of the auto guidance switch.

3. 3

   Disconnect the Switch

   Unplug the electrical connector from the faulty auto guidance switch.

4. 4

   Repair Wiring

   If the diagnostic checks revealed a damaged harness, repair the broken/shorted wire or replace the affected harness section.

5. 5

   Replace the Switch

   If the switch failed the continuity test, pop the old switch out of its cavity and snap the new OEM replacement switch into place.

6. 6

   Reassemble

   Reconnect the electrical connector to the switch and reinstall the armrest trim panels.

7. 7

   Restore Power

   Reconnect the negative battery cable.

8. 8

   Clear and Test

   Turn the key on, clear the error code(s) using the Electronic Service Tool (EST) or the cab display, and test the auto guidance system for normal operation.