John Deere 2370.03 – CLC / VCU / CAB / RLC: Right Extremity Turn Signal Light Circuit Voltage High

The controller monitoring the lighting circuit has detected a higher-than-expected voltage on the right-hand turn signal, marker light, or flasher circuit, which typically indicates a short to power in the wiring harness or the light assembly itself.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 250D
• 300D
• 260E
• 310E
• 310SK
• 315SK
• 544K
• 624K
• 944K
• 770G
• 770GP
• 772G
• 772GP

1. 1

   Isolate Aftermarket Accessories: Remove or disconnect all operator-customized accessories (such as aftermarket flood lights, hazard lights, or window wipers) tied into the cab load center to see if the code clears.

2. 2

   Visual Inspection of Light Assemblies: Inspect the right rear turn signal and right front turn signal housings for physical damage, water intrusion, or an internally shorted bulb/socket.

3. 3

   Wire Harness Test: Using a multimeter, test the right turn signal circuit wiring harness for a short to power. Trace the lines from the light assemblies back to the CLC/VCU.

4. 4

   Controller Pin Check: Inspect the connectors at the Cab Load Controller (CLC) for corrosion, moisture, or bent pins that could be bridging power to the turn signal circuit.

1. 1

   Power down machine

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes during repair.

2. 2

   Test light assembly

   Disconnect the right-hand turn signal/flasher assemblies. Reconnect the battery and turn the machine on. If the 002370.03 code changes to an 'Open Circuit' code (like 002370.05), the short is inside the light assembly. Replace the light assembly.

3. 3

   Repair wiring harness

   If the code remains active with the lights disconnected, the short to power is in the wiring harness. Trace the harness back to the CLC, locate the chafed or melted wire bridging to a power source, and splice/repair the damaged section using OEM-approved weather-sealed connectors.

4. 4

   Replace CLC module

   If the wiring harness tests perfectly continuous with no shorts to power, the internal circuitry of the Cab Load Controller (CLC) has failed. Replace the CLC module.

5. 5

   Verify repair

   Reconnect all components, clear the stored diagnostic trouble codes via the monitor, and cycle the right turn signals and hazard lights to verify the repair.