John Deere 2398.03 – BLC: Outer Worklights on Front of Roof, External Voltage

The control module is detecting voltage on the front roof outer work light pin even when the work lights are commanded OFF. This is likely caused by a voltage back feed in the loom, meaning a short circuit to a power source is feeding voltage backward through the wiring harness into the module.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6090MC
• 6090RC
• 6100MC
• 6100RC
• 6110MC
• 6110RC

1. 1

   Verify the Symptom: Use a multimeter to check for voltage at the front roof outer work light connector pins while the tractor is on but the work light switch is in the OFF position.

2. 2

   Harness Inspection: Inspect the wiring loom (harness) routing from the BLC module to the front roof outer work lights. Look for chafed wires, melted insulation, or pinched areas where the work light power wire might be shorting to a constant 12V/24V power source.

3. 3

   Connector Checks: Inspect the connectors at both the BLC module and the roof work lights for corrosion, water ingress, or bent pins that could bridge circuits and cause a back feed.

4. 4

   Component Isolation: Disconnect the front roof outer work light assemblies completely. If the back feed voltage at the harness disappears, the internal circuitry of the light housing is shorted. If the voltage remains, the short is in the wiring loom.

1. 1

   Power down and disconnect battery

   Power down the tractor and disconnect the battery to prevent electrical damage during repairs.

2. 2

   Disconnect work lights

   Access the front roof outer work lights and disconnect their electrical connectors.

3. 3

   Inspect wiring loom

   Trace the wiring loom from the roof lights back to the BLC module, visually inspecting for any damage or cross-wiring.

4. 4

   Repair or replace wiring

   Repair any damaged wires by splicing and sealing with heat shrink. If the harness is severely melted or damaged, replace the affected harness section.

5. 5

   Replace work light assembly

   If the wiring loom tests fine but the light assembly was causing the back feed, remove the mounting hardware and replace the faulty front roof work light assembly.

6. 6

   Reconnect components

   Reconnect all electrical connectors and the battery.

7. 7

   Clear fault code

   Connect a compatible diagnostic tool (such as John Deere Service ADVISOR or Jaltest) to the tractor to clear the BLC 002398.03 fault code from the module's memory.

8. 8

   Verify repair

   Turn the tractor on and toggle the work lights on and off to verify the repair and ensure the fault code does not return.