Case IH 520567-05 - BCM – BCM: Electrical ignition power relay - open circuit

The control module has detected an open circuit in the electrical ignition power relay circuit. This means the electrical path is broken, preventing the relay from properly energizing the switched power bus when the ignition is turned ON.

• MAGNUM AFS Connect
• Magnum 400 AFS Connect

1. 1

   Ensure the batteries are fully charged, all connections are clean and tight, and the transmission is in neutral or park

2. 2

   Measure the voltage between the ignition power relay and the battery (a 0-volt reading indicates an open circuit on the positive side)

3. 3

   With the ignition switch OFF, check resistance (ohms) between the battery negative terminal and the relay ground circuit to check for a bad ground or severed wire

4. 4

   Remove the ignition power relay and bench test it for internal coil continuity to rule out a failed relay

1. 1

   Power Down

   Turn the ignition switch to the OFF position.

2. 2

   Wait Period

   Wait 2 to 5 minutes after turning off the key before disconnecting the batteries to allow the BCM and other modules to power down correctly and save data.

3. 3

   Disconnect Batteries

   Disconnect the negative battery cable to ensure safety while working on the power distribution circuit.

4. 4

   Locate the Relay

   Access the main power distribution center / fuse box to locate the Ignition Power Relay (often designated as K1 or R3 depending on the specific cab configuration).

5. 5

   Inspect Wiring & Terminals

   Inspect the socket housing and cavities for the ignition relay. Look for pushed-out pins, corrosion, or melted plastic.

6. 6

   Repair/Replace

   If the relay failed the diagnostic bench test, replace the ignition power relay with a new OEM unit. If the relay is good but the circuit is open, repair or replace the damaged wiring harness/cable between the BCM, the ignition switch, and the relay socket.

7. 7

   Reassembly

   Reconnect the batteries, turn the ignition ON, and verify that the BCM successfully energizes the ignition power relay (supplying battery power to the switched power bus) and clears the 520567-05 fault code.