John Deere 2390.03 – RLC: License Plate Light Voltage High

The system detects a voltage higher than 16 volts on the license plate light circuit. This specific code is often designated as '(Eur Only)', meaning it primarily applies to European models equipped with license plate lighting.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7210R
• 7230R
• 7250R
• 7270R
• 7290R
• 7310R
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 9370R
• 9420R
• 9470RT
• 9520RT
• 9570RT
• 9620RX

1. 1

   Test the tractor's battery and alternator output with a multimeter to rule out an overcharging alternator causing system-wide high voltage (above 16 volts).

2. 2

   Inspect the wiring harness running from the RLC module to the license plate light for chafing and shorting to a higher voltage power supply line.

3. 3

   Disconnect the license plate light plug and inspect the pins for corrosion, moisture, or bridging that could cause a short to power.

4. 4

   With the light switched on, use a multimeter at the connector to verify the actual voltage reaching the lamp.

1. 1

   Disconnect Power

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

2. 2

   Access the Harness

   Locate the license plate light assembly (typically mounted on the rear fender or cab roof depending on the model) and trace the wiring harness back toward the cab.

3. 3

   Repair Wiring

   If a short to power is found in the harness during diagnostics, cut out the damaged section of the wire and splice in a new section using weather-sealed heat-shrink butt connectors.

4. 4

   Replace the Lamp

   If the wiring tests fine but the lamp assembly itself is internally shorted or damaged, unbolt the old license plate light housing, disconnect the plug, and install a replacement unit.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery. Use a John Deere diagnostic tool (Service ADVISOR) or the tractor's command center display to clear the RLC 002390.03 code.

6. 6

   Test Operation

   Turn on the tractor's lighting system and verify that the license plate light illuminates correctly and the fault code does not return.