Case IH 520600-03 - BCM – BCM: Work lamp #1 - short circuit to B+

The control module has detected a short to battery positive (B+) voltage on the circuit supplying power to Work Lamp #1. This means the circuit is receiving 12V power when it shouldn't be, or the power feed wire has rubbed through and is touching another live wire.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series (Magnum 200, 340, 400)
• Case IH Puma Series (Puma 200, 215, 230)

1. 1

   Identify the Lamp: Locate 'Work Lamp #1' on the machine (refer to the operator's manual, as this is typically a specific front hood or lower cab/fender light depending on the lighting package).

2. 2

   Disconnect and Retest: Disconnect the pigtail connector at Work Lamp #1. Turn the ignition and work lights on. If the fault code changes from a 'short to B+' (03) to an 'open circuit' or 'current below normal' code, the short is internal to the lamp assembly itself.

3. 3

   Harness Inspection: If the 520600-03 code remains active while the lamp is unplugged, the short to B+ is in the machine's wiring harness. Trace the wiring from the lamp back to the BCM, looking for pinched wires, melted insulation, or areas where the harness rubs against the frame or other live circuits.

4. 4

   BCM Pin Check: Inspect the BCM harness connectors for water ingress, corrosion, or bent pins that could be bridging a 12V pin to the Work Lamp #1 output pin.

1. 1

   Power Down

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

2. 2

   Wiring Repair

   If a harness short was found during diagnostics, cut out the damaged section of the wire. Splice in a new section of appropriately gauged wire using weather-sealed (heat-shrink) butt connectors. Wrap the repaired section in protective loom.

3. 3

   Lamp Replacement

   If applicable (short is internal to the lamp assembly): Unbolt the faulty work lamp from its mounting bracket. Install the new work lamp assembly and tighten the mounting hardware. Plug the lamp's DT connector into the machine's wiring harness.

4. 4

   Reassembly & Clearing

   Reconnect the battery ground. Turn the key to the ON position and use the AFS Pro monitor to clear inactive fault codes.

5. 5

   Verification

   Turn on the work lights and verify that Work Lamp #1 illuminates correctly and the 520600-03 code does not return.