Case IH 520569-00 - BCM – BCM: Map lamp - too many loads or faulty load

The control module is detecting an excessive current draw on the map lamp circuit. This typically means there is a short circuit in the wiring, an internal short in the lamp assembly, or an incorrect/aftermarket bulb installed that draws more amperage than the circuit is designed to handle.

• MAGNUM AFS Connect
• Magnum 240
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 380
• Magnum 400
• Steiger AFS Connect
• Steiger 350
• Steiger 535
• Steiger 580

1. 1

   Verify that the map lamp bulb is the correct OEM specification (Wedge, 3-1/4 GE #W5W). An incorrect aftermarket bulb will trigger the fault.

2. 2

   Inspect the map lamp connector (X-717 Right C Post Map Lamp connector, 3-pole male) for melted plastic, corrosion, or pushed-out terminal pins.

3. 3

   Check the wiring between the BCM and the map lamp for chafing or a short-to-ground, particularly where the harness routes up the C-post or into the overhead console.

4. 4

   Verify the main battery cables for compromised connections or severe voltage drops, which can cause erratic cab electrical behavior.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent further shorting or damage to the BCM.

2. 2

   Access the Map Lamp

   Locate the map lamp assembly, which is typically mounted on the Right C-Post or the overhead console.

3. 3

   Remove the Bezel

   Carefully pry off the map lamp bezel (Part # 360364A1) to expose the lamp assembly and bulb.

4. 4

   Inspect and Replace the Bulb

   Remove the bulb. If the filament is shattered or the glass is blackened, replace it with a standard W5W wedge bulb.

5. 5

   Test the Assembly

   If the bulb is fine, disconnect the 3-pole X-717 connector. Test the lamp assembly for internal continuity. If the switch or internal housing is shorted, the entire lamp assembly (Part # 83882C91) must be replaced.

6. 6

   Repair Wiring (if necessary)

   If the connector is melted due to the excessive load, splice in a new 3-pole connector (Part # 47924679) and new terminal pins (Part # 47924686).

7. 7

   Reassemble and Clear Codes

   Reconnect the battery, turn the key on, and use the Pro 1200 display / diagnostic tool to clear the BCM fault codes. Test the map lamp to ensure the fault does not return.