John Deere 522620.03 – CLC (Cab Load Center), VLC (Vehicle Load Center), or SCL (Steering Column Lever): Horn Circuit Voltage High / Vehicle Horn Short to Power

The control module is detecting a higher-than-expected voltage on the horn circuit, which typically means the circuit is shorted to a power source, or a switch/relay is stuck in the closed/powered position.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 9470RT
• 9520RT
• 9570RT
• 744K
• 744K Series II
• 944K Hybrid
• 524KII
• 624K
• CH570
• CH670
• 200CLC
• 230CLC
• 270CLC

1. 1

   Examine all components, especially the battery connection points. A buildup of acid or dirt on the battery can cause voltage irregularities.

2. 2

   Turn the key switch to the ON position. Locate the horn fuse (e.g., F14 - 10 Amp fuse on CLC models). Push the horn switch; if the horn operates normally but the code persists, the issue may be intermittent or sensor-related.

3. 3

   Locate the horn relay in the load center. A relay that is internally stuck closed will constantly feed power to the circuit, triggering a 'Short to Power' code.

4. 4

   Check the steering column lever or the dedicated horn button. If the switch is physically stuck or internally shorted, it will continuously send a high-voltage signal to the CLC.

5. 5

   Inspect the wiring harness between the CLC, the horn switch, the relay, and the physical horn for chafed wires that may be shorting against a 12V/24V power source.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery terminal to ensure safety while working on the electrical system.

2. 2

   Inspect and Replace the Relay

   Access the Cab Load Center (CLC) or Vehicle Load Center (VLC) fuse/relay panel. Remove the horn relay and test it with a multimeter. If it fails to open/close properly or shows continuity when unpowered, replace the relay.

3. 3

   Inspect and Replace the Switch

   If the relay is good, test the horn switch (AT222153 or equivalent steering column lever) for internal shorts. If the switch has failed closed, remove the steering column shroud or dash panel, unplug the switch harness, and install a replacement switch.

4. 4

   Repair Wiring

   If both the relay and switch are functioning properly, trace the wiring harness using the machine's specific electrical schematic. Locate the short-to-power (often where wires pass through bulkheads or articulate) and splice/heat-shrink the damaged wire.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery, turn the key to the ON position, and clear the CLC/VLC diagnostic trouble codes via the cab monitor. Test the horn to ensure the code does not return.