Case IH 2386-03 - BCM – BCM (Body Control Module): Rotating Beacon Light Command - Voltage Above Normal, Or Shorted To High Source (Short circuit to B+)

The control module has detected that the circuit controlling the rotating beacon light is shorted to battery voltage (B+). This means voltage is present on the circuit when it shouldn't be, or the current draw indicates a direct short to a 12V power source.

• MAGNUM AFS Connect
• Combines (AFX8010, 8240 series)
• Steiger
• Magnum
• Puma
• MX series

1. 1

   Inspect the Beacon Light Assembly by disconnecting it; if the fault code status changes from Active to Inactive, the internal circuitry of the beacon is shorted

2. 2

   Test the beacon light relay (e.g., K-29) and the beacon light switch (e.g., S-41) in the cab distribution panel for an internal short constantly feeding 12V to the circuit

3. 3

   Check the dedicated beacon fuse (e.g., Fuse F-53) to see if it has blown due to the short

4. 4

   With the battery disconnected, perform a harness continuity test between the BCM, the relay, and the beacon light connector, looking for continuity to any constant 12V (B+) power source

5. 5

   Visually inspect the outer roof harness and cab mid-work light harnesses for pinched wires, melted insulation, or chafing against the cab frame

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery cable to prevent further electrical damage.

2. 2

   Isolate the Short

   Based on your multimeter readings, trace the wiring harness from the roof beacon connector back to the cab distribution panel.

3. 3

   Repair Wiring

   If a chafed or melted wire is found shorting to a 12V source, cut out the damaged section and splice in a new wire using weather-sealed heat-shrink butt connectors. Wrap the repaired section in protective loom.

4. 4

   Replace Faulty Components

   If the wiring is intact but the relay failed the continuity test, replace the beacon light relay. If the short is isolated to the beacon light housing itself, replace the rotating beacon light assembly.

5. 5

   Reassemble and Test

   Reconnect the battery, turn the ignition on, and clear the inactive fault codes from the BCM via the Pro 700/1200 display. Turn on the beacon light switch to verify proper operation without the code returning.