John Deere 1550.05 – ECU / VLC: Air Conditioner Compressor Clutch Circuit Fault

The control unit has detected an open circuit in the A/C compressor clutch circuit. The system triggers this code when the current in the circuit drops below 500 milliamperes (0.5 amps), suggesting a disconnection, wire fatigue, or a break in the circuit. When this fault is active, the A/C compressor will not engage, resulting in a complete loss of air conditioning functionality.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5085M
• 5095M
• 5100M
• 5105M
• 5115ML
• 8130
• 8230
• 8330
• 8430
• 8530
• 250D
• 300D Series II
• 370E
• 410E
• 460E
• 540G-III
• 548G-III
• 3029 Diesel Engine
• 7000 Series
• 9000 Series
• 326D
• 328D
• 332D

1. 1

   Inspect the wiring harness and connectors associated with the A/C compressor clutch circuit for any signs of physical damage, disconnections, wire fatigue, or corrosion

2. 2

   Verify that the relay and fuse supplying power to the A/C compressor clutch circuit are intact and functioning properly

3. 3

   Use a multimeter to measure the current in the A/C compressor clutch circuit to confirm it is below 500 milliamperes (0.5 amps)

4. 4

   Test the A/C compressor clutch coil for continuity, as a malfunctioning or burned-out clutch coil is a common cause of an open circuit

1. 1

   Locate the Compressor

   Locate the A/C compressor on the engine block and trace the wiring harness back toward the Vehicle Load Center (VLC) or ECU.

2. 2

   Check Power Supply

   Inspect the A/C compressor clutch fuse and relay in the fuse panel. Replace any blown fuses or faulty relays.

3. 3

   Inspect Connectors

   Disconnect the A/C compressor clutch pigtail connector. Inspect the pins for corrosion, pushed-out pins, or damage. Clean or repair the connector if necessary.

4. 4

   Test the Clutch Coil

   Using a multimeter set to Ohms, check for continuity across the A/C compressor clutch coil pins. If the multimeter reads an open circuit (infinite resistance/OL), the clutch coil has failed internally. You must replace the A/C compressor clutch assembly (or the entire compressor).

5. 5

   Test the Harness

   If the clutch coil has good continuity, check the machine's wiring harness for continuity between the control module (ECU/VLC) and the compressor connector. Repair any broken wires or secure loose connections.

6. 6

   Clear and Verify

   Reconnect all components, clear the 001550.05 fault code via the monitor, and test the A/C system to ensure the compressor engages and the code does not return.