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

The Vehicle Load Center (VLC) has detected that the amperage draw from the air conditioning compressor clutch circuit is below the normal operating range. This indicates an open circuit or high resistance preventing the proper amount of electrical current from reaching the compressor clutch, which stops the clutch from engaging and disables the air conditioning system's cooling function.

• 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.