Case IH 520594-00 - BCM – BCM: License plate lights - too many loads or faulty load

The Body Control Module (BCM) has detected an excessive current draw on the license plate light circuit. This "overload" condition is typically caused by a short circuit, the installation of incorrect (higher wattage) bulbs, or unauthorized aftermarket accessories being spliced directly into the license plate lighting circuit.

• MAGNUM AFS Connect
• Magnum AFS Connect series
• Magnum 400 AFS Connect
• Puma 200
• Puma 215
• Puma 230
• T8 series

1. 1

   Check the license plate light bulbs to ensure they are the correct OEM wattage and type. Incorrect aftermarket bulbs can draw too much current.

2. 2

   Inspect the rear wiring harness for any aftermarket accessories (extra work lights, beacons, trailer wiring) improperly spliced into the license plate light circuit.

3. 3

   Trace the license plate light wiring harness back to the BCM. Look for chafing, pinched wires, or exposed copper causing a short to ground or power.

4. 4

   Disconnect the license plate light assemblies completely. Turn the machine on and check if the fault code changes to an open circuit code to isolate the fault to the lamp assembly or bulbs.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to ensure safety while working on the electrical system.

2. 2

   Remove Unauthorized Loads

   If any aftermarket lights or accessories are spliced into the license plate light circuit, remove them and wire them to an appropriate auxiliary circuit with its own relay and fuse.

3. 3

   Inspect and Replace Bulbs/Assemblies

   Remove the license plate light assemblies. If the housings are melted, corroded, or shorted internally, replace the entire assembly. If the housing is fine, replace the bulbs with the correct OEM-specified voltage/wattage bulbs.

4. 4

   Repair the Harness

   If the wiring harness was found to be chafed or shorting against the tractor chassis, cut out the damaged section and repair it using weather-sealed (heat-shrink) butt connectors, or replace the harness section entirely.

5. 5

   Reassemble and Test

   Reconnect the license plate light assemblies and the battery.

6. 6

   Clear Codes

   Turn the ignition on, activate the lights, and use the diagnostic tool to clear the BCM fault codes. Verify that the license plate lights illuminate correctly and that the 520594-00 code does not return.