Case IH 12514 – Electronic Brake Module (EBM): Left or Right or Front AoH end of stroke switches in fault or open circuit

The control module has lost communication with one of the Air-over-Hydraulic (AoH) end of stroke switches, which monitor the maximum travel of the brake actuator piston. This is typically caused by a disconnected plug, a broken wire in the harness, or an internal failure of the switch itself.

• Case IH Puma Series (170, 185, 200, 215, 230, and CVX/Tier 4 variants)
• Case IH Optum Series
• Case IH Magnum Series

1. 1

   Identify the faulty circuit using the service manual (Front: Switch S-084 / Connector X971, Rear Left: Switch S-085 / Connector X965, Rear Right: Switch S-086 / Connector X966)

2. 2

   Inspect the wiring harness leading to the affected connector for chafing, breaks, or corrosion which commonly causes an open circuit

3. 3

   Unplug the connector and test the end of stroke switch for continuity using a multimeter to determine if the switch has failed internally

4. 4

   Check the Air-over-Hydraulic converter for mechanical binding, fluid leaks, or air pressure issues that might cause the piston to over-travel and permanently trigger the switch

1. 1

   Safely park the tractor on level ground, apply the parking brake, and turn off the engine.

2. 2

   Depressurize Systems

   Relieve all air pressure from the pneumatic brake system and depressurize the hydraulic brake circuit to prevent injury.

3. 3

   Access the Converter

   If working on the front AoH converter, remove the front wheels (Procedure 44.511) to gain access. Ensure the machine is properly supported with heavy-duty lifting equipment.

4. 4

   Locate the affected Air-over-Hydraulic (AoH) converter (Front, Rear Left, or Rear Right).

5. 5

   Disconnect the electrical connector (X971, X965, or X966) from the end of stroke switch.

6. 6

   Unthread and remove the faulty end of stroke switch from the AoH converter body.

7. 7

   Install the new switch and tighten to OEM torque specifications.

8. 8

   Reconnect the wiring harness.

9. 9

   Bleed the hydraulic brake system to remove any introduced air.

   Perform this step if the entire AoH converter was replaced.

10. 10

    Clear the fault code using a diagnostic tool and test the braking system for proper operation.