Case IH 520442-05 - BCM – BCM: Roof mounted headlamp high beam left - open circuit

The control module has detected that the electrical circuit supplying power to the left roof-mounted high beam headlamp is incomplete or broken. This is typically caused by a burnt-out bulb, a disconnected plug, a broken wire in the cab roof harness, or a poor ground connection.

• MAGNUM AFS Connect
• Magnum AFS Connect 250
• Magnum AFS Connect 280
• Magnum AFS Connect 310
• Magnum AFS Connect 340
• Magnum AFS Connect 380
• Magnum AFS Connect 400
• Steiger AFS Connect
• Optum AFS Connect

1. 1

   Inspect the left roof-mounted high beam headlamp to see if the bulb is visibly burnt out or if the LED diodes have failed.

2. 2

   Swap the left roof headlamp with the right roof headlamp. If the fault code changes to the right side (or the left side now works), the headlamp assembly is the culprit.

3. 3

   Access the headlamp connector in the upper left corner of the cab roof. Check for loose pins, moisture intrusion, or corrosion.

4. 4

   With the high beams commanded ON, use a multimeter to check for 12V at the supply pin on the harness side. Check the ground pin for continuity to the chassis.

5. 5

   If there is no voltage, trace the wiring harness from the roof headlamp back to the BCM to locate the break or pinched wire (often found under the headliner or cab access panels).

1. 1

   Turn off the tractor ignition and disconnect the negative battery cable to prevent accidental shorts while working on the BCM circuits.

2. 2

   Access the left roof-mounted headlamp by removing the retaining screws on the cab roof bezel.

3. 3

   Disconnect the wiring harness plug from the back of the headlamp assembly.

4. 4

   If the headlamp is faulty: Plug the replacement headlamp into the harness, seat it into the roof bezel, and secure the retaining hardware.

5. 5

   If the wiring is faulty: Repair the open circuit in the harness. Splice and heat-shrink any broken wires found between the BCM output and the roof connector. Ensure the ground strap for the cab roof lights is clean and tight.

6. 6

   Reconnect the negative battery cable.

7. 7

   Turn the ignition ON and activate the high beams via the rotary switch/stalk to verify the left roof headlamp illuminates.

8. 8

   Clear the inactive fault code from the BCM using the AFS Pro display or an electronic service tool.