Case IH 520443-06 - BCM – Body Control Module (BCM): Right roof-mounted high beam headlamp short circuit to ground

The fault code indicates a short circuit to ground on the power circuit supplying the right roof-mounted high beam headlamp. The BCM has detected that the current strength at the output to the lamp is out of range (often reading near zero ohms of resistance). This occurs when the power wire touches a ground source before reaching the bulb, or if the headlamp assembly itself has suffered an internal failure/short.

• MAGNUM AFS Connect
• Case IH Magnum series (e.g., AFS Connect Magnum 180-380)
• Case IH Puma series (e.g., 165, 180, 195, 210, 225)
• Case IH Steiger series
• Case IH Patriot Sprayers (e.g., 3330)

1. 1

   Check the bulb/globe to verify the correct wattage is installed (e.g., a 55w globe instead of a 35w globe can draw excessive current and mimic a short circuit)

2. 2

   Inspect the lighting circuit fuses, as a short to ground will often blow the corresponding fuse before or as the fault is logged

3. 3

   Disconnect the right roof-mounted headlamp assembly and use a multimeter to check the headlamp internally for a short circuit

4. 4

   With the headlamp and BCM disconnected, use a multimeter to measure the resistance between the power supply wire for the right high beam and a known good chassis ground (a reading near zero ohms confirms the wiring harness is shorted to ground)

1. 1

   Power Down

   Turn off the ignition and disconnect the battery to prevent further electrical damage during testing.

2. 2

   Access the Harness

   Gain access to the wiring harness routing from the cab roof down to the BCM.

3. 3

   Inspect for Damage

   Visually inspect the wiring harness for chafing, pinched wires, or melted insulation, paying special attention to areas where the harness passes through the cab pillars or roof panels.

4. 4

   Repair the Circuit

   If a damaged wire is found, repair the wiring harness using OEM-approved splicing and heat-shrink methods, or replace the affected harness section.

5. 5

   Replace the Headlamp

   If the wiring tests good but the headlamp assembly failed the internal resistance test, install a new right roof-mounted headlamp assembly.

6. 6

   Reassemble and Clear Codes

   Reconnect the headlamp, BCM, and battery. Using a Case IH approved diagnostic scan tool, clear the DTCs from the BCM.

7. 7

   Validate Repair

   Turn on the ignition and activate the high beams to ensure the right roof-mounted headlamp operates correctly and the fault code does not return.