Case IH 520577-06 - BCM – BCM: Turn light rear right - short circuit to ground

The Body Control Module (BCM) has detected that the electrical circuit supplying power to the rear right turn signal is drawing excessive current, indicating that the power wire is touching a ground source (short circuit to ground) before it reaches the bulb, or the bulb/socket itself is internally shorted.

• MAGNUM AFS Connect
• Optum AFS Series
• Magnum Series
• Steiger AFS Series

1. 1

   Inspect the rear right turn signal housing, lens, and bulb for physical damage, water intrusion, or corrosion.

2. 2

   Remove the rear right turn signal bulb and check if it is internally shorted. Inspect the socket for melted plastic or corroded contacts bridging the power and ground terminals.

3. 3

   Disconnect the harness connector at the rear right turn light and at the BCM. Use a multimeter to measure resistance between the turn signal power pin on the harness and a known good chassis ground. A reading of zero (or near zero) ohms indicates a short circuit to ground in the wiring harness.

4. 4

   Trace the wiring harness from the rear right light back to the BCM, checking for areas where the wire insulation may have rubbed through against the chassis, fenders, or moving parts.

1. 1

   Turn the ignition switch to the OFF position and disconnect the battery to prevent damage to the BCM.

2. 2

   If the diagnostic checks reveal a faulty bulb or melted socket, replace the bulb or the tail light assembly.

3. 3

   If the harness is shorted to ground, locate the chafed or damaged section of the wire.

4. 4

   Repair the wire by cutting out the damaged section, soldering in a new piece of wire of the same gauge, and sealing it with heat-shrink tubing to prevent moisture ingress.

5. 5

   Secure the harness with zip ties or loom to ensure it does not rub against the chassis again.

6. 6

   Reconnect the battery, turn the ignition ON, and test the right turn signal and hazard lights to verify the repair. Clear the inactive fault code from the BCM.