John Deere 002368.03 – Cab Control Unit / Lighting Controller: Left Turn Signal Voltage High

Fault code 002368.03 indicates a 'Voltage High' condition in the left-hand wide vehicle warning light (extremity light) circuit, which is integrated into the left turn signal. The control module has detected abnormally high voltage on this circuit, typically caused by a short circuit to a power source, a faulty light assembly, or an internal control module error. This condition may result in the light failing to operate correctly or staying on continuously, which can negatively affect vehicle visibility and safety.

• 6M Series
• 6R Series
• 7J Series
• 7R Series
• 8100-8410 Series
• 8R Series
• 8RT Series
• 8RX Series
• 9R Series
• 9RT Series
• 9RX Series
• 9x30 Series

1. 1

   Visually inspect the left-hand extremity light assembly for physical damage, water ingress, or corrosion, and check the wiring harness leading to the light for chafing, pinching, or melted insulation.

2. 2

   Check for a short to power: disconnect the harness from the light, turn the key ON (engine OFF), and measure voltage between the signal wire pin and chassis ground. A reading of 12V+ without the turn signal activated indicates a short.

3. 3

   Inspect all related harness connectors (including the main module connector and X132 interconnects) for corroded, bent, or pushed-out pins.

4. 4

   Test the light assembly independently by connecting it directly to a 12V power source and ground to check for internal circuitry faults.

5. 5

   Isolate the circuit by disconnecting intermediate connectors along the harness path to locate the short.

1. 1

   Repair harness damage

   If a short circuit or damaged wiring is found, replace the affected wires using the same gauge wire. Seal all connections with heat-shrink tubing to prevent moisture intrusion.

2. 2

   Clean or replace connectors

   Clean corroded connector pins with contact cleaner. If damage is severe, replace the connector or pins.

3. 3

   Replace light assembly

   If the light assembly fails independent testing or is physically damaged, replace it with the correct OEM part for your specific model and serial number.

4. 4

   Address control module fault

   If wiring and the light assembly are in good condition, the fault may be within the control module's output driver. Consult a certified dealer for module diagnostics, replacement, and programming.

5. 5

   Clear codes and verify

   Reconnect all components, start the tractor, and clear the fault codes. Activate the left turn signal and hazard lights to verify correct operation and ensure the code does not return.