Case IH 518686-02 - ACM – ACM: Hitch settings adjustment knob switch circuit fault

The control module is receiving an erratic, out-of-range, or intermittent electrical signal from the potentiometer/switch that controls the 3-point hitch settings (such as draft, position, or drop rate) located on the armrest console.

• MAGNUM AFS Connect
• Magnum Series (MX215, MX245, MX285, 235, 245, 255, 275, 305, 335, 340)
• Steiger Series (280, 330)
• Puma Series (125, 140, 155)

1. 1

   Verify if the code is active or stored, as active faults will immediately affect hitch operation.

2. 2

   Inspect the physical condition of the hitch settings adjustment knob for damage, sticking, or liquid spills on the armrest console.

3. 3

   Access the underside of the armrest and inspect the wiring harness connecting the hitch knob potentiometer to the ACM for loose pins, corrosion, or chafed wires.

4. 4

   Use a multimeter to test the resistance of the switch/potentiometer as you turn the knob; resistance should change smoothly without dropping to zero or showing an open circuit.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent static discharge or shorting sensitive ACM components.

2. 2

   Disassemble the Armrest

   Carefully remove the cover panels of the armrest console to access the Armrest Controller Module and the switch assemblies.

3. 3

   Replace the Switch/Knob

   If the potentiometer/switch tests faulty (erratic resistance), disconnect its harness and remove the retaining nut or clips holding it to the console. Install the new switch and reconnect the harness.

4. 4

   Inspect ACM Filter Capacitors

   If the switch and wiring are intact, the issue may be internal to the ACM. Check for shorted filter capacitors on the inputs to the ICs inside the ACM caused by static discharge. If this is the case, the ACM must be repaired or replaced.

5. 5

   Reassemble and Power Up

   Reinstall the armrest covers and reconnect the battery.

6. 6

   Recalibrate the Hitch Controller

   After replacing hitch control components, recalibrate the hitch system. Ensure the tractor is parked and cannot move (movement will abort calibration and throw a 9320 or 3010 fault code). Ensure engine speed is running above 1500 RPM (failure triggers a 9318 or 9321 fault code). Follow the on-screen display prompts to complete the hitch raise/lower calibration sequence.