Case IH 518441-02 - ACM – ACM: Volume increase switch circuit fault

A circuit error (typically an open circuit, short to ground, or disconnected state) in the media/radio control switches located on the tractor's armrest. The control module is detecting a voltage or resistance value outside of the expected parameters when the audio source or volume up button is pressed, or it has lost communication with the switch entirely.

• MAGNUM AFS Connect
• Magnum AFS Connect series (250, 280, 310, 340, 380, 400)
• Steiger / Quadtrac AFS Connect series

1. 1

   Perform a visual and physical inspection of the media/radio switch cluster on the Multicontroller armrest for dust, dirt, or liquid spills that can cause contacts to stick or short.

2. 2

   Cycle the volume and audio source buttons repeatedly with the machine off to see if they feel physically stuck or lack their normal tactile click.

3. 3

   Lift the armrest console cover and inspect the wiring harness connecting the media switch panel to the main ACM board for pinched wires, loose connector pins, or corrosion.

4. 4

   Disconnect the switch and test for continuity across the switch pins with a multimeter while pressing the button. If the circuit remains open when pressed, the switch has failed internally.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery ground cable to prevent any short circuits while working near the ACM.

2. 2

   Disassemble the Armrest

   Remove the Torx screws securing the top plastic bezel/cover of the Multicontroller armrest. Carefully pry the cover upward.

3. 3

   Disconnect the Switch

   Locate the media/radio switch cluster. Unplug the small electrical connector linking the switch to the ACM harness.

4. 4

   Remove the Faulty Switch

   Depress the plastic retaining tabs (or remove the mounting screws, depending on the exact trim level) holding the switch assembly into the armrest bezel and push the switch out.

5. 5

   Install the New Part

   Snap the replacement switch assembly into the bezel and reconnect the electrical harness. Ensure the connector clicks securely into place.

6. 6

   Reassemble and Test

   Reinstall the armrest cover and secure the screws. Reconnect the battery, turn the key to the ON position, and test the audio source and volume buttons while watching the AFS Pro 1200 display. Verify that the fault code changes from 'Active' to 'Stored' or clears entirely.