Case IH 520583-00 - BCM – BCM: Reverse lights - too many loads or faulty load

The control module has detected an overcurrent condition on the reverse light circuit. The underlying condition is typically a short circuit to ground in the wiring harness, a failed bulb that has shorted internally, water intrusion in the light housing, or the installation of incorrect aftermarket bulbs/accessories that draw more amperage than the circuit is designed to handle.

• MAGNUM AFS Connect
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400
• Steiger AFS Connect

1. 1

   Inspect the rear tail light and reverse light assemblies on the cab corners and fenders for physical damage, melted plastic, or water intrusion.

2. 2

   Remove the reverse light bulbs to check if they are blown, shorted, or if an incorrect, high-wattage aftermarket bulb was installed.

3. 3

   Disconnect the reverse light housings from the main wiring harness, turn the key ON, and engage reverse. If the code changes to an open circuit code, the short is located inside the light housing or the bulb itself. If the 520583-00 code remains active, the short to ground is located in the tractor wiring harness.

4. 4

   With the lights disconnected, use a digital multimeter to check for continuity to ground on the reverse light power supply wire. Inspect the harness routing near the rear axle, cab suspension pivot points, and fenders for pinch points or chafing.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery isolator switch to prevent accidental shorts or module damage during repair.

2. 2

   Access the Lights

   Remove the lens or unbolt the affected reverse/tail light assembly from the rear cab corners or fenders.

3. 3

   Replace Components

   If a bulb is faulty or the wrong wattage, replace it with the exact OEM specification bulb. If the internal wiring of the tail light assembly is shorted or heavily corroded due to water ingress, replace the entire tail light assembly.

4. 4

   Repair Wiring

   If the harness is chafed, cut out the damaged section of wire, solder in a new section, and seal it with dual-wall adhesive heat shrink tubing. Secure the harness with zip ties away from moving parts.

5. 5

   Test and Clear

   Reconnect the battery isolator, turn the ignition ON, and engage reverse to verify the reverse lights illuminate properly. Use the AFS Pro display or the Case IH Electronic Service Tool (EST) to clear the inactive 520583-00 fault code from the BCM.