Case IH 520569-05 - BCM – Body Control Module (BCM): Map lamp - open circuit

The Body Control Module (BCM) has detected an open circuit in the map lamp (or dome/reading lamp) electrical circuit. The BCM monitors the output circuit to the map lamp, and if it detects infinite resistance or a lack of expected current draw (0V return) when the lamp is commanded on, it logs this fault.

• MAGNUM AFS Connect
• Magnum 180
• Magnum 200
• Magnum 215
• Magnum 220
• Magnum 240
• Magnum 250
• Magnum 275
• Magnum 280
• Magnum 305
• Magnum 310
• Magnum 335
• Magnum 340
• Magnum 380
• Steiger 385
• Steiger 435
• Steiger 535
• Steiger 580
• MX Series
• Axial-Flow 1644
• Axial-Flow 2166
• Axial-Flow 2344
• Axial-Flow 2366
• Axial-Flow 2388
• Axial-Flow 2588
• Axial-Flow 5088
• Axial-Flow 7120
• Axial-Flow 7240
• Axial-Flow 8910
• Axial-Flow 9230
• Cotton Picker 420
• Cotton Picker 620
• Cotton Picker 2555
• Cotton Picker CPX620
• Maxxum Series
• C Series
• CX Series

1. 1

   Verify the Malfunction: Test the map lamp by toggling the manual switch on the lamp housing and by opening the cab door (if equipped with a door jamb switch) to see if the lamp fails to illuminate in all states.

2. 2

   Inspect the Bulb: A burned-out bulb is the most frequent cause of an open circuit code in lighting systems. Remove the lens and visually inspect the bulb filament.

3. 3

   Check Fuses: Inspect the interior room lamp / dome lamp fuse (typically a 10A fuse in the cab fuse panel). A blown fuse will cut power to the circuit, though it usually affects multiple interior lights.

4. 4

   Circuit Continuity Test: Disconnect the map lamp harness connector. Use a multimeter to check for continuity between the BCM harness connector and the map lamp connector. Infinite resistance indicates a broken wire (open circuit).

5. 5

   Switch Test: Test the map lamp switch for continuity. The switch should close the circuit when pressed; if it remains open, the switch is faulty.

1. 1

   Isolate Power

   Turn the ignition switch to the OFF position and disconnect the battery negative terminal (or pull the interior lighting fuse) to prevent accidental short circuits during repair.

2. 2

   Remove the Lens

   Insert an appropriate plastic trim tool into the edge of the map lamp / dome lamp housing and carefully pry off the center cover or clear lens.

3. 3

   Replace the Bulb

   Pull the old bulb from the housing. If the filament is broken, install a new OEM incandescent bulb or an upgraded LED direct-fit replacement into the socket.

4. 4

   Repair Wiring (If Applicable)

   If the bulb was not the issue and your diagnostic checks revealed a broken wire, trace the harness back to the BCM. Repair the break in the wire and secure it with heat-shrink tubing, or replace the damaged connector pin.

5. 5

   Reassemble

   Snap the map lamp lens or center cover back into the housing.

6. 6

   Test and Clear Codes

   Reconnect the battery or replace the fuse. Turn the ignition ON and test the map lamp. The BCM should detect the completed circuit and change the fault code status from 'Active' to 'Inactive/Stored,' allowing you to clear it.