Case IH 520580-00 - BCM – BCM: Turn light front right - too many loads or faulty load

The fault code indicates an electrical current anomaly on the front right turn signal circuit. The Body Control Module (BCM) monitors the power consumption (load) of the lighting circuits and detects a current draw that is outside the expected parameters. This can be caused by overcurrent (short circuit, corrosion, too many loads) or undercurrent (blown bulb, broken wire, or aftermarket LED installation).

• MAGNUM AFS Connect
• AFS Connect Magnum 180
• AFS Connect Magnum 200
• AFS Connect Magnum 220
• AFS Connect Magnum 240
• AFS Connect Magnum 250
• AFS Connect Magnum 280
• AFS Connect Magnum 310
• AFS Connect Magnum 340
• AFS Connect Magnum 380 Tier 4B
• Puma
• Optum
• Maxxum

1. 1

   Visually inspect the front right turn signal bulb to see if it is blown or if the filament is damaged

2. 2

   Check if the incandescent bulb was recently replaced with an aftermarket LED, which lowers resistance and triggers a faulty load

3. 3

   Inspect the light socket for water intrusion, rust, or corrosion, which can alter electrical resistance

4. 4

   Trace the wiring from the front right turn signal back to the BCM, looking for pinched wires, frayed insulation, or shorts to the chassis

5. 5

   Use a multimeter to verify if the BCM is sending the correct voltage to the light socket when the turn signal is activated

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent accidental short circuits during repair.

2. 2

   Replace the Bulb/Clean the Socket

   If the bulb is blown, replace it with the exact OEM-specified incandescent wattage. If the socket is corroded, clean the contacts with electrical contact cleaner or replace the pigtail/assembly.

3. 3

   Address LED Upgrades

   If you are intentionally using LED bulbs, you must install a load resistor (typically 6 Ohm 50W) in parallel with the turn signal wiring to compensate for the load drop and satisfy the BCM's diagnostic parameters.

4. 4

   Repair Wiring

   Splice and heat-shrink any damaged sections of the wiring harness that are shorting to the frame.

5. 5

   Clear Codes

   Reconnect the battery, turn the key on, and test the turn signal. Use a diagnostic tool (like the New Holland/Case IH EST) to clear the stored fault code from the BCM.

6. 6

   BCM Replacement (Worst Case)

   If the wiring and bulb are perfect but the fault persists and the pin at the BCM has no output, the BCM's internal low-side switch or microcontroller may be burned out due to a previous severe short circuit. The BCM will need to be replaced and reprogrammed.