Case IH 518986-00 - BCM – BCM: Work lamp #6 - too many loads or faulty load

The control module has detected an excessive current draw or an incorrect electrical load on the specific circuit powering Work Lamp #6. This is typically caused by a failing bulb drawing too much amperage, an internal short in an LED driver, damaged wiring, or unauthorized aftermarket lights being spliced into the factory circuit.

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1. 1

   Check the Work Lamp #6 circuit to ensure no aftermarket accessories or extra work lights have been spliced into the wiring harness, which would overload the BCM circuit.

2. 2

   Disconnect Work Lamp #6 and swap it with a known good lamp from another position (e.g., Work Lamp #5). Clear the codes and test. If the fault code changes to the new position, the lamp assembly is faulty. If the code remains 518986-00, the issue is in the wiring harness or the BCM itself.

3. 3

   Inspect the wiring harness leading to the lamp for chafing, pinched wires, or melted insulation that could be causing a short to ground or short to power.

4. 4

   Verify that the BCM grounding points are secure and free of corrosion.

5. 5

   Use a CAN-capable diagnostic scan tool to monitor live data from the BCM. Check if the BCM is commanding the light on and what voltage/amperage it is reporting.

1. 1

2. 2

   Power down machine

   Turn off the ignition and disconnect the negative battery cable to prevent accidental shorts or module damage during the repair.

3. 3

   Access the lamp

   Locate Work Lamp #6 on the cab or fender. Disconnect the electrical pigtail connector at the rear of the lamp housing.

4. 4

   Inspect connectors

   Check the pins on both the harness side and the lamp side for signs of melting, water intrusion, or corrosion. Clean with contact cleaner or replace the pigtail if heat damage is present.

5. 5

   Repair wiring harness

   If the diagnostic checks revealed a short in the wiring, cut out the damaged section and splice in new wire using weather-sealed, heat-shrink butt connectors. Remove any unauthorized spliced-in loads.

6. 6

   Replace the lamp

   If the lamp failed the swap test, unbolt the mounting bracket hardware, remove the faulty lamp, and mount the replacement assembly.

7. 7

   Reassemble components

   Plug the harness connector securely into the new lamp. Reconnect the negative battery cable.

8. 8

   Clear codes and test

   Turn the ignition ON. Use your diagnostic scan tool to clear the inactive 518986-00 fault code from the BCM. Turn on the work lamps and verify that the light operates correctly and the code does not return.