Case IH 520550-05 - BCM – BCM: Left extended arm turn indicator - Current Below Normal or Open Circuit

The control module is attempting to send electrical current to the left turn signal located on the machine's extended arm, but it detects little to no current flowing through the circuit. This is typically caused by a broken wire, a disconnected wiring harness plug, or a burnt-out bulb/LED assembly.

• MAGNUM AFS Connect
• Trident 5550
• Magnum
• Steiger
• Puma
• Maxxum
• Farmall

1. 1

   Inspect the left extended arm turn indicator assembly for physical damage, water intrusion, or a visibly burnt-out bulb/LED

2. 2

   Trace the wiring harness from the left extended arm back to the BCM looking for broken wires, chafing, or disconnected plugs

3. 3

   Disconnect the turn signal plug and check the connector pins for moisture, dirt, or corrosion

4. 4

   Use a multimeter to test the circuit's resistance and verify if the open circuit is inside the light assembly or within the wiring harness

1. 1

   Power Down

   Turn off the machine and disconnect the battery to protect the BCM from accidental shorts during repair.

2. 2

   Address the Open Circuit

   If the light assembly is faulty: Remove the mounting hardware on the extended arm, disconnect the pigtail, and install a new turn signal/flasher assembly. If the wiring is damaged: Repair the broken wire using weather-sealed butt connectors, or replace the damaged section of the harness. If connectors are corroded: Clean the pins with electrical contact cleaner and apply dielectric grease before reconnecting.

3. 3

   Reassemble and Reconnect

   Secure the wiring harness and reconnect the battery.

4. 4

   Clear Codes and Test

   Use a CNH EASy diagnostic tool or a compatible aftermarket scanner (such as OTR Performance or Jaltest) to clear the inactive 520550-05 fault code from the BCM. Activate the left turn signal to confirm the repair.