John Deere 521555.03 – RLC (Cab Roof Module / Roof Lighting Controller): Front Roof Warning (NA Only) or Front Corner Roof Light (Eur Only) Right Voltage High / Right Outer Worklight on Front of Roof Voltage High

The controller is detecting a higher-than-expected voltage on the monitor pin for the front roof outer right work light circuit. This typically indicates an open circuit (such as a blown bulb, broken wire, or disconnected plug) or a short to battery voltage in the wiring harness.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8R Series
• 8RT Series
• 8RX Series
• 8225R
• 8245R
• 8320R
• 8400R
• 9R Series
• 9RT Series
• 9RX Series
• 9470RT
• 9520RT
• 9570RT
• 6R Series
• 7R Series
• 6110R-6215R
• 7200R-7310R

1. 1

   Inspect the front roof outer right work light assembly for physical damage, cracked lenses, or water intrusion.

2. 2

   Disconnect the right outer work light and inspect the connector for corrosion, pushed-back pins, or moisture.

3. 3

   Use a multimeter to check the power wire leading to the light for a short to battery voltage. Check the ground circuit for high resistance.

4. 4

   Swap the right outer work light with the left outer work light. If the fault code changes to the left side (e.g., 521554.03), the light assembly itself has failed internally. If the code remains 521555.03 on the right side, the issue is in the cab roof wiring harness or the RLC module itself.

1. 1

   Park the tractor on a level surface, turn off the engine, and remove the key.

   Park the tractor on a level surface, turn off the engine, and remove the key.

2. 2

   Disconnect the negative battery cable to prevent electrical shorts during the repair.

   Disconnect the negative battery cable to prevent electrical shorts during the repair.

3. 3

   Safely access the front roof lighting array on the right side of the cab roof.

   Safely access the front roof lighting array on the right side of the cab roof.

4. 4

   Unplug the electrical pigtail connector from the back of the front roof outer right work light.

   Unplug the electrical pigtail connector from the back of the front roof outer right work light.

5. 5

   If the wiring harness is damaged, repair the broken/shorted wire using OEM-approved weather-pack connectors and heat shrink.

   If the wiring harness is damaged, repair the broken/shorted wire using OEM-approved weather-pack connectors and heat shrink.

6. 6

   If the light assembly is faulty, remove the mounting bolt/bracket securing the light to the cab roof.

   If the light assembly is faulty, remove the mounting bolt/bracket securing the light to the cab roof.

7. 7

   Install the replacement work light assembly and tighten the mounting hardware.

   Install the replacement work light assembly and tighten the mounting hardware.

8. 8

   Reconnect the electrical connector, ensuring the weather seal is intact and it clicks securely into place.

   Reconnect the electrical connector, ensuring the weather seal is intact and it clicks securely into place.

9. 9

   Reconnect the negative battery cable.

   Reconnect the negative battery cable.

10. 10

    Turn the key to the ON position, clear the stored RLC fault codes via the CommandCenter display, and turn on the work lights to verify the code does not return.

    Turn the key to the ON position, clear the stored RLC fault codes via the CommandCenter display, and turn on the work lights to verify the code does not return.