John Deere CAB2348 – CAB: Cab Roof Lights 3 and 4 High Open Circuit

The Cab Control Unit (CAB) has detected a break in the electrical circuit (open circuit) for the high beam function of cab roof lights 3 and 4. This condition prevents electrical current from completing its path, causing the lights to fail to illuminate when commanded.

• 8R Series
• 7R Series
• Combines

1. 1

   Visually inspect cab roof lights 3 and 4, their connectors, and visible wiring harness sections for cut wires, loose connections, or corrosion

2. 2

   Check the main fuse box for blown fuses related to the cab or lighting circuits, and inspect associated relays for failed internal coils

3. 3

   Remove bulbs from lights 3 and 4 to visually inspect filaments, or use a multimeter to check for continuity across the bulb terminals (an 'OL' reading indicates a failed bulb)

4. 4

   With cab roof lights switched on, use a multimeter to check for voltage at the connector for lights 3 and 4 to isolate the open circuit location

1. 1

   Disconnect power

   Park the machine on a level surface, turn off the engine, and disconnect the negative battery cable.

2. 2

   Access wiring

   Remove the cab roof panel or headliner as needed to gain access to the roof light wiring harness.

3. 3

   Trace the circuit

   Trace circuit cc# 585 from the CAB controller to the connectors for roof lights 3 and 4, checking intermediate connectors and junction points.

4. 4

   Test continuity

   Disconnect both ends of the suspected wire segment and test with a multimeter. An 'OL' or infinite resistance reading confirms the open circuit location.

5. 5

   Repair or replace wiring

   Splice in a new section of wire using sealed connectors, repair/replace damaged pins or connectors, or replace the relevant harness section if damage is extensive.

6. 6

   Test the Repair

   Once the repair is complete, reconnect the battery and turn on the lights to ensure they are functioning correctly.

7. 7

   Clear Fault Codes

   After confirming the repair, use the tractor's diagnostic interface or a service tool to clear the stored CAB 2348 fault code.