Case IH 520592-06 - BCM – BCM: Mirror heater indicator - short circuit to ground

The control module has detected that the electrical circuit providing power or signal to the mirror heater indicator light is shorting directly to a ground source (the machine's chassis or a ground wire). This prevents the indicator from functioning and can disable the mirror heating circuit to protect the system.

• MAGNUM AFS Connect
• Magnum 180 AFS Connect
• Magnum 200 AFS Connect
• Magnum 220 AFS Connect
• Magnum 240 AFS Connect
• Magnum 250 AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Inspect the wiring harness running from the BCM to the cab control console/pillar where the mirror heater switch is located. Look for pinched wires, chafing, or melted insulation that could cause the indicator wire to touch bare metal (ground).

2. 2

   Disconnect the mirror heater switch and use a multimeter to check for continuity to ground on the indicator circuit wire. If the short disappears when unplugged, the switch has an internal short. If it remains, the wiring harness is the culprit.

3. 3

   Inspect the BCM harness connectors for moisture intrusion, corrosion, or bent pins, which can bridge the indicator circuit to a neighboring ground pin.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the Switch

   Remove the trim panels on the cab pillar or side console to access the rear of the mirror heater switch.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a chafed wire in the harness, cut out the damaged section, splice in a new section of wire using weather-sealed heat-shrink butt connectors, and wrap the harness in protective loom.

4. 4

   Replace the Switch

   If the switch was internally shorted, depress the retaining tabs on the switch body, push it out of the bezel, and snap the new OEM switch into place. Reconnect the harness plug.

5. 5

   Reassembly and Testing

   Reconnect the battery. Turn the ignition on, clear the inactive BCM fault codes using the AFS Pro display or a diagnostic tool, and activate the mirror heater to verify the indicator illuminates without throwing the 520592-06 code.