Case IH 2380-00 - BCM – BCM: Trailer marker lamps - too many loads or faulty load

The control module has detected a current draw on the trailer marker lamp circuit that exceeds the programmed threshold. This is typically caused by too many loads (splicing too many auxiliary marker lamps) or a faulty load (defective device or dead short).

• MAGNUM AFS Connect
• Case IH Magnum

1. 1

   Isolate the Load: Disconnect the trailer from the tractor's 7-pin receptacle. If the fault code goes away or changes to an 'open circuit' code, the issue is isolated to the trailer. If the code persists, the short/fault is on the tractor side.

2. 2

   Count the Loads: Verify if the trailer has an excessive number of marker lamps that might be drawing too much total current for the BCM's programmed limit.

3. 3

   Inspect for Shorts: Check the trailer wiring harness and the tractor's receptacle for a fault in the fixed wiring, such as a wire rubbed bare and shorting to the chassis.

4. 4

   Check Bulb Compatibility: If the trailer was recently retrofitted with LEDs, ensure they are CAN-compatible LED lamps with specific resistor packs that mimic standard halogen current draw.

1. 1

   Disconnect the Trailer

   Unplug the trailer to protect the tractor's BCM from repeated overload tripping.

2. 2

   Inspect and Repair Wiring

   Trace the brown/black marker light circuit on the trailer. Repair any pinched wires, corroded splices, or exposed copper that is causing a short to ground.

3. 3

   Reduce Circuit Load

   If the trailer has too many incandescent marker lamps, reduce the load by removing unnecessary lamps or upgrading the entire marker circuit to CAN-compatible LED lamps.

4. 4

   Replace Defective Lamps

   Identify and replace any single defective marker lamps or housings that are internally shorted.

5. 5

   Clear and Retest

   Reconnect the trailer to the tractor, turn on the headlights/marker lights, and verify that the BCM no longer detects an overload and the fault code clears.