Case IH 3997-06 - BCM – BCM: Electrical Accessory Power Relay - Current Above Normal or Grounded Circuit

The control module has detected excessive current draw on the control circuit for the Electrical Accessory Power Relay. This almost always indicates that the wire providing power/ground from the module to the relay coil is chafed and touching the chassis (shorted to ground), or the internal coil of the relay itself has collapsed and shorted out.

• MAGNUM AFS Connect
• Magnum
• Steiger
• Puma
• Maxxum
• Optum
• Axial-Flow
• Patriot

1. 1

   Visually inspect the Accessory Power Relay (typically in the cab fuse/relay panel) for melted plastic around the socket or a burnt electrical smell.

2. 2

   Perform a relay swap test by exchanging the Accessory Power Relay with a known good relay of the exact same type (e.g., horn or work light relay). If the code clears or changes to an open circuit, the relay is faulty.

3. 3

   Test the harness with a multimeter: disconnect the battery, remove the relay, disconnect the BCM harness connector, and measure resistance between the relay control pin (usually Pin 85 or 86) and a known good chassis ground. Continuity indicates a shorted wire.

1. 1

   Disconnect Power

   Turn off the master disconnect switch or remove the negative battery cable to prevent module damage.

2. 2

   Isolate the Short

   If the multimeter test confirmed a short to ground in the wiring, trace the harness from the relay block back to the BCM. Pay close attention to areas where the harness passes through metal bulkheads, bends tightly around cab framing, or routes near moving seat components.

3. 3

   Repair the Wiring

   Once the chafed or pinched wire is found, cut out the damaged section. Splice in a new section of wire using weather-resistant crimp connectors and seal it with adhesive-lined heat shrink tubing.

4. 4

   Replace the Relay

   If the wiring is intact but the relay coil tested shorted (near 0 ohms across pins 85 and 86), discard the old relay.

5. 5

   Reassemble and Clear Codes

   Plug the new relay into the socket, reconnect the BCM, and restore battery power. Turn the key to the ON position and verify that the accessory circuit powers up and the 3997-06 code moves to an 'inactive' state or clears entirely.