Case IH 520583-06 - BCM – BCM: Reverse lights - short circuit to ground

This fault code indicates that the electrical circuit supplying power to the reverse (back-up) lights has shorted to ground. This means the voltage on the reverse light circuit has dropped to 0V unexpectedly, usually because the positive power wire is physically touching the tractor's metal chassis, a ground wire, or there is an internal dead short within the light assembly itself.

• MAGNUM 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 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Inspect the rear reverse light assemblies for physical damage, water intrusion, or melted housings which can cause internal shorting.

2. 2

   Disconnect the reverse light assemblies from the main wiring harness.

3. 3

   With the lights disconnected, use a multimeter to check for continuity between the reverse light power supply wire and the chassis ground. If continuity to ground is still present, the short is in the wiring harness between the BCM and the rear connectors. If the short disappears, the fault is an internal short inside one of the reverse light assemblies.

4. 4

   Inspect the wiring harness routing along the rear fenders, cab suspension pivot points, and near the rear hitch/PTO area, as these are common areas for wire insulation to rub through and touch the frame.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery cable to prevent electrical spikes during repair.

2. 2

   Isolate the Fault

   Disconnect the connectors at both rear reverse lights.

3. 3

   Test the Circuit

   Reconnect the battery temporarily, turn the key to the ON position (engine off), and clear the fault code via the AFS Pro display. Shift the FNRP (Forward/Neutral/Reverse/Park) lever into reverse. If the code does not return, replace the faulty reverse light assembly. If the code does return, proceed to harness repair.

4. 4

   Trace and Repair Wiring

   Disconnect the battery again. Trace the reverse light circuit from the rear of the cab back to the BCM. Locate the pinched or chafed wire.

5. 5

   Splice the Wire

   Cut out the damaged section of the wire. Strip the ends and use an OEM-approved environmental splice (crimp connector with adhesive-lined heat shrink) to repair the circuit.

6. 6

   Secure the Harness

   Re-wrap the harness in protective loom and secure it with zip ties away from moving parts or sharp metal edges.

7. 7

   Final Verification

   Reconnect the reverse lights and the battery. Turn the key on, shift into reverse, and verify that the reverse lights illuminate and the 520583-06 code remains inactive.