Massey Ferguson 10.X.09 – AIRCON: Air Conditioning Evaporator Temperature Sensor Open Circuit

When this fault is logged, the system detects that the circuit for the evaporator temperature sensor is open (broken wire, disconnected plug, or internally failed sensor). As a safety consequence to prevent the evaporator core from freezing over, the air conditioning compressor is turned off and cooling is disabled.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 8600 Series
• 8660
• 8680
• 7600 Series
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7700 Series
• 7700S Series
• 5600 Series
• 5700SL Series
• 4700 Global Series
• 5700 Global Series
• 6700 Global Series
• 4707
• 4708
• 4709
• 4710
• 6400 Series
• 7400 Series
• 8400 Series
• 6465
• 6480
• 7495
• 8480

1. 1

   Connect a PC or AGCO Electronic Diagnostic Tool (EDT) to monitor the live data for the evaporator temperature sensor signal. Look for default or impossible values indicating an open circuit.

2. 2

   Inspect the wiring harness leading to the HVAC unit and the sensor connector for physical damage, corrosion, or disconnected pins.

3. 3

   Unplug the sensor and measure its resistance across the pins with a multimeter. A healthy thermistor should return a specific resistance (often around 10 ohms at 25°C). If the multimeter reads 'OL' (Open Loop) or infinite resistance, the sensor itself has failed internally.

4. 4

   If the sensor tests good, check the continuity of the wiring harness between the sensor connector and the AIRCON module pins to locate the break in the wire.

1. 1

   Access the HVAC Unit

   Locate the evaporator housing, typically found in the cab roof or under the cab floor depending on the specific tractor model. Remove the necessary access panels or headliner.

2. 2

   Disconnect the Sensor

   Locate the evaporator temperature sensor (usually inserted directly into the fins of the evaporator core). Unplug its electrical connector.

3. 3

   Remove the Sensor

   Carefully pull the probe out of the evaporator core.

4. 4

   Install the New Sensor

   Insert the replacement sensor probe into the exact same location in the evaporator fins to ensure accurate temperature readings.

5. 5

   Reconnect and Reassemble

   Plug the electrical connector back in, ensuring it clicks securely. Reinstall all cab panels or roof access covers.

6. 6

   Clear Codes

   Use the AGCO EDT or onboard diagnostic menu to clear the 10.00.09 fault code.

7. 7

   Test Operation

   Turn on the tractor and engage the A/C. Verify that the compressor clutch engages and the system blows cold air without logging the code again.