Case IH 520581-00 - BCM – BCM: Marker light front & rear left - too many loads or faulty load

The circuit supplying power to the left-side marker lights (front and rear) is drawing more electrical current than the module expects, which typically points to a short to ground, an overloaded circuit, or an incorrect/faulty component drawing excessive amperage.

• MAGNUM AFS Connect
• Magnum
• Steiger
• Puma

1. 1

   Visually inspect the front left and rear left marker light assemblies for physical damage, water intrusion, or melted housings

2. 2

   Verify that the correct bulbs or LED assemblies are installed, as an incorrect aftermarket bulb can cause a faulty load error if its amperage draw exceeds the BCM's programmed threshold

3. 3

   Inspect the wiring harness routing to the left marker lights for chafing, pinched wires, or exposed copper that could cause a short to ground

4. 4

   Perform a disconnect test by unplugging the left marker light assemblies one at a time and clearing the codes to see if the fault changes from an overcurrent state to an open circuit state, isolating the fault to the light assembly or the wiring harness

1. 1

   Turn off the machine and disconnect battery power to prevent further damage to the BCM.

   Turn off the machine and disconnect battery power to prevent further damage to the BCM.

2. 2

   If the diagnostic checks reveal a damaged wire, repair the wiring harness using OEM-approved sealed splices.

   If the diagnostic checks reveal a damaged wire, repair the wiring harness using OEM-approved sealed splices.

3. 3

   If a marker light assembly is internally shorted or water-damaged, remove the mounting hardware, disconnect the pigtail connector, and install a new marker light assembly.

   If a marker light assembly is internally shorted or water-damaged, remove the mounting hardware, disconnect the pigtail connector, and install a new marker light assembly.

4. 4

   Reconnect battery power.

   Reconnect battery power.

5. 5

   Turn on the marker lights and use a diagnostic tool to clear the BCM fault code. Verify that the lights illuminate correctly and the code does not return.

   Turn on the marker lights and use a diagnostic tool to clear the BCM fault code. Verify that the lights illuminate correctly and the code does not return.