Case IH 520580-05 - BCM – Body Control Module (BCM): Turn light front right - open circuit

The control module is commanding the front right turn signal to illuminate, but it detects no electrical current draw. This typically points to a burned-out bulb filament, a disconnected wiring harness plug, a broken wire, or severe corrosion in the bulb socket preventing electrical contact.

• MAGNUM AFS Connect
• Case IH Maxxum Series (MX100, MX110, MX120, MX135)
• Case IH Loader Landscapers (570LXT, 570MXT, 570NXT)
• Case IH Backhoes and Forklifts (580K, 580L, 580M, 580N, 590, 585G, 586G, 588G)

1. 1

   Perform a visual bulb inspection by removing the front right turn signal lens to check for a broken filament

2. 2

   Inspect the bulb socket for moisture, dirt, or corrosion that could prevent a solid electrical connection

3. 3

   Perform a ground circuit test using a multimeter to verify continuity between the ground pin on the light socket and the chassis ground

4. 4

   Conduct a power supply test by activating the right turn signal and checking for 12V pulsing power at the socket with a multimeter

5. 5

   Check harness continuity by disconnecting the harness at the BCM and checking the signal wire to isolate any breaks or chafing

1. 1

   Turn off the machine, remove the key, and ensure the lighting switch is in the OFF position.

2. 2

   Locate the front right turn signal assembly.

3. 3

   Remove the amber lens cover or twist the bulb socket out from the rear of the housing.

   Usually secured by screws, depending on the specific model.

4. 4

   Remove the bulb and inspect it.

   If the filament is broken or the glass is darkened, replace it with a new 12V 21W bulb.

5. 5

   Clean the socket contacts if the bulb is intact.

   Use electrical contact cleaner and a small wire brush to remove any corrosion. Apply a small amount of dielectric grease to prevent future moisture intrusion.

6. 6

   Replace the entire turn signal lamp assembly if necessary.

   Do this if the socket is melted or heavily corroded, or if the housing is cracked.

7. 7

   Repair any broken wires in the harness.

   Locate the break, strip the wire ends, solder them together, and seal the repair with marine-grade heat-shrink tubing.

8. 8

   Reinstall the bulb, socket, and lens cover.

9. 9

   Verify the repair.

   Turn the ignition key on and activate the right turn signal to verify the light flashes correctly and the BCM fault code clears.