Case IH 518986-06 - BCM – BCM: Work lamp #6 - short circuit to ground

The power supply circuit for Work Lamp #6 has a direct path to ground. This is typically caused by a chafed wire touching the tractor's chassis, a pinched harness, or an internal short circuit within the work lamp assembly itself. To protect the circuit from overheating or fire, the control module disables the power output to this specific lamp.

• MAGNUM AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect
• Steiger AFS Connect
• Quadtrac AFS Connect

1. 1

   Visual Inspection: Locate Work Lamp #6 on the tractor. Inspect the exposed wiring harness leading to the lamp for any obvious signs of chafing, melting, or pinching against the cab frame or mounting brackets.

2. 2

   Component vs. Harness Isolation: Disconnect the electrical connector directly at Work Lamp #6.

3. 3

   Check Active Codes: Turn the ignition on. If the fault code changes from 518986-06 (Short to ground) to 518986-05 (Open circuit), the wiring is intact and the short circuit is internal to the work lamp itself.

4. 4

   Harness Testing: If the code remains 518986-06 with the lamp disconnected, the short is in the wiring harness. Disconnect the harness from the BCM and use a digital multimeter to test for continuity between the Work Lamp #6 power pin and chassis ground. Continuity confirms a shorted harness.

1. 1

   Power Down

   Turn off the tractor and engage the battery disconnect switch to ensure the BCM is fully powered down.

2. 2

   Address the Lamp (If internally shorted)

   Unbolt the defective Work Lamp #6 from its mounting bracket. Install the replacement lamp and plug in the connector.

3. 3

   Address the Harness (If wiring is shorted)

   Trace the wiring harness from the lamp back to the BCM to locate the damaged section.

4. 4

   Repair Wiring

   Cut out the chafed or melted section of the wire. Splice in a new section of wire of the correct gauge using weather-sealed, heat-shrink butt connectors. Wrap the repaired section in protective loom.

5. 5

   Re-route

   Secure the harness with zip ties, ensuring it is routed away from sharp metal edges or moving parts to prevent a recurrence.

6. 6

   Clear and Test

   Reconnect the battery, turn on the ignition, and clear the inactive fault codes via the AFS Pro 1200 monitor. Turn on the work lamps to verify that Work Lamp #6 illuminates and the code does not return.