Case IH 520442-00 - BCM – BCM: Roof mounted headlamp high beam left - too many loads or faulty load

The control module has detected an excessive current draw on the circuit supplying the left roof-mounted high beam headlamp. This indicates that the circuit is overloaded, which is typically caused by a defective headlamp assembly (internal short), a partial short to ground in the wiring harness, or unauthorized aftermarket accessories spliced into the circuit.

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

1. 1

   Inspect the left roof-mounted high beam headlamp for signs of physical damage, water intrusion, or internal failure.

2. 2

   Verify that no aftermarket light bars or additional accessories have been spliced into the left roof headlamp circuit, triggering the 'too many loads' condition.

3. 3

   Disconnect the left roof headlamp and inspect the pigtail connector for corrosion, melted pins, or moisture, which can cause a partial short.

4. 4

   Perform a circuit isolation test: with the headlamp disconnected, turn the tractor on and check active fault codes. If the code changes to 520442-05 (open circuit), the fault is isolated to the headlamp assembly. If 520442-00 remains, the fault is in the cab roof wiring harness.

1. 1

   Power Down

   Turn off the tractor, remove the key, and ensure the lighting circuit is unpowered.

2. 2

   Isolate the Component

   Access the front left roof-mounted headlamp on the cab roof and disconnect its electrical connector.

3. 3

   Harness Testing

   Trace the cab roof wiring harness back toward the BCM. Look for pinched wires, chafed insulation, or areas where the harness may be rubbing against the cab frame, repairing any damaged sections.

4. 4

   Remove Unauthorized Loads

   If any non-OEM accessories are wired into this circuit, remove them and wire them to a dedicated relayed circuit instead.

5. 5

   Replace the Lamp

   If the harness tests good (or the code changed to an open circuit during the diagnostic phase), replace the faulty left roof headlamp assembly.

6. 6

   Clear and Verify

   Reconnect the new headlamp, power on the tractor, clear the fault codes via the AFS Pro 1200 display or diagnostic tool, and test the high beams to verify the repair.