Case IH 520585-03 - BCM – BCM: Right brake indicator light - Voltage Above Normal, or Shorted to High Source

The control module is detecting battery voltage (12V) on the right brake indicator light circuit when it should not be present (such as when the brake pedal is not depressed).

• MAGNUM AFS Connect
• Magnum Series (210, 245, 305, 340, 380, AFS Connect models)
• Puma Series (165, 180, 195, 210, 225)
• Maxxum Series (100, 110, 125, 140, older 51/52 series)
• Steiger / STX Series (STX375, STX450, STX500)
• Patriot Sprayers (3230, 3330, SPX3320)
• Axial-Flow Combines (7230, 8230, 9230)

1. 1

   Remove the right brake indicator light bulb and inspect the socket for melted plastic, corrosion, or bridged contacts that could feed power backward.

2. 2

   Locate the brake light switch at the brake pedal linkage and disconnect the harness. If the short to B+ goes away, the switch is internally shorted.

3. 3

   With the battery disconnected, use a multimeter to test the wiring harness between the right brake indicator light, the brake switch, and the BCM for continuity to any constant 12V power wires.

4. 4

   Disconnect the BCM harness and inspect the pins for water intrusion, corrosion, or bent pins bridging a power circuit to the brake light circuit.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes or further damage to the BCM during repair.

2. 2

   Access the Components

   Remove the necessary cab trim panels to access the brake pedal linkage (for the switch) and the right rear indicator light assembly.

3. 3

   Replace the Bulb/Socket

   If the diagnostic checks revealed a melted right brake indicator socket, splice in a new socket using heat-shrink butt connectors and install a new bulb.

4. 4

   Replace the Brake Switch

   If the switch was found to be internally shorted, unbolt the faulty switch from the pedal assembly. Install the new OEM brake switch and plug in the harness. Ensure the switch is properly adjusted so it only engages when the pedal is pressed.

5. 5

   Repair Wiring

   If a harness short was found, carefully unloom the affected section of the wiring harness. Cut out the chafed/melted section of the wire, solder in a new section of wire of the same gauge, and seal it with marine-grade heat shrink. Re-loom and secure the harness away from moving parts.

6. 6

   Test the System

   Reconnect the battery. Turn the key to the ON position and clear the BCM fault codes. Depress the right brake pedal to verify the indicator light illuminates properly and the 520585-03 code does not return.