Case IH 518676-03 - ACM – ACM: Internal failure / Voltage High in the Hitch settings selector knob circuit

The control module is receiving a voltage signal from the hitch settings selector knob that exceeds the maximum expected threshold. This is typically caused by a short circuit to a high-voltage source, an open ground circuit causing the signal to float high, or an internal mechanical/electrical failure of the knob itself.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series
• Case IH Steiger AFS Connect Series

1. 1

   Inspect the Multi-function handle and armrest control panel for physical damage, liquid spills, or debris around the hitch settings selector knob.

2. 2

   Disconnect the knob's harness from the ACM and inspect the connector pins for corrosion, moisture, or pushed-out pins.

3. 3

   Using a multimeter, verify that the 5-volt reference supply to the knob is within limits (a high 5V reference can trigger related codes like 1014).

4. 4

   Check the ground circuit for continuity; an open ground will cause the sensor's signal voltage to read artificially high.

5. 5

   Test the signal wire between the knob and the ACM for a short to a 12V or 5V power source.

1. 1

   Power Down

   Turn off the tractor key and disconnect the battery to prevent electrical spikes during repair.

2. 2

   Access the ACM / Armrest

   Carefully remove the trim panels on the Case IH AFS Connect armrest to access the underside of the hitch control switch cluster.

3. 3

   Remove the Faulty Component

   Disconnect the electrical connector leading to the hitch settings selector knob. Unclip or unbolt the knob/switch assembly from the armrest console.

4. 4

   Install the New Part

   Seat the replacement knob assembly into the console and secure it. Reconnect the electrical harness, ensuring the connector clicks firmly into place.

5. 5

   Reassemble and Power Up

   Reinstall the armrest trim panels. Reconnect the tractor battery and turn the ignition key to the ON position.

6. 6

   Clear Codes & Calibrate

   Use the AFS Pro 1200 monitor or the Case IH Electronic Service Tool (EST) to clear the inactive 518676-03 fault code. You may need to perform a rear hitch calibration procedure so the ACM can learn the new minimum and maximum voltage values of the replacement knob.