John Deere 2368.03 – Rear Chassis Module (VLC): Left Turn Signal Circuit Short to Power

The control module has detected that the voltage on the left turn signal output circuit is higher than expected when the circuit is not being commanded on. This typically means the left turn signal wire is rubbing against a constant 12V power source, or there is an internal short bridging the pins inside the trailer socket.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7R Series
• 8R Series

1. 1

   Inspect the trailer socket for heavy corrosion, water intrusion, dirt, or bent pins that could be bridging the 12V auxiliary power pin to the left turn signal pin.

2. 2

   Isolate the socket by disconnecting the trailer socket wiring harness connector at the rear of the tractor. Turn the key ON and check if the 002368.03 code changes to an 'Open Circuit' code (002368.05) or goes inactive. If it does, the short is inside the socket itself.

3. 3

   With the tractor ON but the turn signal switch OFF, use a digital multimeter to probe the left turn signal pin at the trailer socket. If you read 12V, there is an active short to power.

4. 4

   Trace the wiring harness from the trailer socket back to the Rear Chassis Module (VLC). Look for pinch points, melted insulation, or areas where the harness rubs against the chassis.

1. 1

   Power Down

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

2. 2

   Clean or Replace the Socket

   If the diagnostic checks isolated the short to the trailer socket, spray the inside of the socket with electrical contact cleaner and remove any debris. If the socket is internally corroded or melted, unbolt it from the mounting bracket and cut/disconnect the wiring. Install a new trailer socket, ensuring the dark green wire (standard John Deere left turn signal wire) is pinned correctly.

3. 3

   Repair the Wiring Harness

   If the socket is fine but the harness is damaged, locate the chafed section of the wire. Cut out the damaged copper, splice in a new section of appropriately gauged wire, and seal the repair with marine-grade adhesive heat-shrink tubing to prevent moisture ingress.

4. 4

   Re-route the Harness

   Secure the repaired harness with zip ties, ensuring it is routed away from sharp chassis edges or moving linkage components.

5. 5

   Test the System

   Reconnect the battery. Turn the key ON, clear the stored fault codes via the cab monitor, and activate the left turn signal. Verify that the lights flash correctly and the code does not return.