Case IH 520602-03 - BCM – BCM: Work lamp #2 - short circuit to B+

The Body Control Module (BCM) has detected that the circuit for Work Lamp #2 is receiving battery voltage (B+) when it should not be. This unwanted power condition occurs when an unintended electrical path exists between the work lamp's power or control circuit and another constant power source, or if the circuit is shorted internally.

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

1. 1

   Inspect the wiring harness leading to Work Lamp #2 for chafing, melting, or pinched wires that could be bridging the lamp's circuit to a constant 12V/B+ power source.

2. 2

   Disconnect Work Lamp #2. If the fault code changes from a short circuit to B+ (03) to an open circuit code, the short is likely internal to the LED/halogen work lamp assembly itself.

3. 3

   With the lamp disconnected and the tractor keyed on (but lamp commanded off), use a multimeter to check for voltage at the lamp connector. If voltage is present, the wiring harness is shorted to power somewhere between the lamp and the BCM.

4. 4

   Inspect the BCM connectors for water ingress, corrosion, or bent pins, which can cause voltage to bleed across terminals.

1. 1

   Power Down

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

2. 2

   Access the Circuit

   Locate Work Lamp #2 (exact location depends on the tractor's specific lighting configuration, e.g., front beltline, rear fender, or upper cab).

3. 3

   Repair Wiring

   If the diagnostic checks revealed a damaged harness, splice and solder the damaged wires, sealing them with marine-grade heat shrink.

4. 4

   Replace the Lamp

   If the lamp is internally shorted, unbolt the mounting bracket, disconnect the pigtail, and install a replacement work lamp.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery, turn the key to the ON position, and use the AFS Pro 1200 monitor or a diagnostic tool to clear the inactive BCM fault codes.

6. 6

   Test

   Turn on the work lights via the Multicontroller armrest encoder to verify Work Lamp #2 illuminates correctly without triggering a new fault code.