John Deere 521554.06 – RLC (Roof Lighting Controller / Cab Roof Module): Right Worklight on Cab Frame or Right Xenon (HID) Worklight on Cab Frame, Current Too High

The circuit controlling the right-side worklight mounted on the cab frame (grab rail light) is drawing excessive amperage. This is typically caused by a short circuit to ground (earth) within the wiring harness, or an internally shorted bulb/light housing. The control software will limit or disable the worklight function to protect the circuit.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6120
• 6220
• 6320
• 6420
• 6520
• 6620
• 6820
• 6920
• 6230
• 6330
• 6430
• 6530
• 6630
• 6830
• 6930
• 6090MC
• 6090RC
• 6100MC
• 6100RC
• 6110MC
• 6110RC
• 5080R
• 5090R
• 5100R
• 5080RN
• 5090RN
• 5100RN

1. 1

   Inspect the right worklight on the cab frame/grab rail for physical damage, water ingress, or melted plastic, which often causes internal shorts.

2. 2

   Locate and inspect the specific connector for this light (often identified as connector X162F-2, X115F, X116F, or circuit E020-R) for corrosion or melted pins.

3. 3

   Trace the wiring harness from the right cab frame down to the RLC module, looking for pinch points, chafing against the cab frame, or degraded insulation causing the power wire to touch bare metal (ground).

4. 4

   Perform a circuit isolation test: Disconnect the light assembly and turn the lights on. If the code changes from 521554.06 (Current Too High) to 521554.05 (Current Too Low / Open Circuit), the short is isolated to the light assembly or bulb itself. If the .06 code remains, the short is in the machine's wiring harness.

1. 1

   Turn off the tractor, remove the key, and locate the right worklight on the cab frame.

   Ensure the machine is powered down before beginning work on the electrical circuit.

2. 2

   Disconnect the wiring harness connector at the light assembly.

   This isolates the light assembly from the main harness.

3. 3

   Remove the bulb from the housing and inspect it.

   If the filament is melted across the posts or the base is shorted, replace the bulb.

4. 4

   Inspect the housing internals.

   If the bulb is fine but the housing internals are melted or corroded together, unbolt the worklight from the grab rail bracket and replace the entire assembly.

5. 5

   Test the wiring harness for a short to ground.

   If the isolation test proves the short is in the wiring harness, use a multimeter to test for continuity between the power pin on the harness connector and the tractor frame (ground).

6. 6

   Trace the wire back toward the RLC.

   Open the wire loom at suspected pinch points (especially where the harness routes into the cab roof).

7. 7

   Repair any bare wires.

   Use heat-shrink butt connectors to repair damaged wires and re-loom the harness.

8. 8

   Reconnect the worklight and verify the repair.

   Turn the key on, activate the worklights, and verify that the RLC 521554.06 code moves to a 'Stored' state and the light functions normally. Clear the codes.