Case IH 518598-02 - ACM – ACM (Armrest Control Module): Front/rear hitch selector switch circuit fault

Circuit fault (erratic signal, open circuit, or short to ground/power) originating from the respective switch on the operator's armrest.

• MAGNUM AFS Connect
• Steiger
• Puma

1. 1

   Inspect the physical switch on the armrest (either the Auto Cruise or Hitch Selector switch, depending on which code is actively logging). Check for physical damage, sticking buttons, or liquid intrusion (spilled drinks are a common cause of ACM switch failures).

2. 2

   Check the sub-harness connecting the switch to the main Armrest Control Module board. Look for pinched wires or loose connector pins.

3. 3

   Back-probe the switch connector to verify if the switch is sending the correct voltage signal to the ACM when toggled.

4. 4

   Test for continuity across the switch contacts and ensure there is no short to ground.

1. 1

   Power Down

   Turn off the tractor, remove the key, and turn off the battery disconnect switch to prevent electrical spikes.

2. 2

   Access the ACM

   Carefully remove the retaining screws on the underside or perimeter of the AFS Connect armrest console to lift the top cover/bezel.

3. 3

   Isolate the Switch

   Locate the specific switch assembly (Auto Cruise or Front/Rear Hitch Selector) and disconnect its pigtail connector from the ACM harness.

4. 4

   Test or Replace

   If the switch failed the multimeter continuity test, remove the retaining clips holding the switch into the armrest bezel and swap in the replacement switch. If the switch tested good, the fault lies in the ACM sub-harness. Repair any broken wires or replace the armrest sub-harness.

5. 5

   Reassembly

   Reconnect the switch, seat it back into the bezel, and secure the armrest cover.

6. 6

   Clear Codes

   Turn the battery disconnect back on, power up the tractor, and use the AFS Pro display (or a diagnostic tool) to clear the inactive fault codes. Test the switch functionality to ensure the code does not return.