Massey Ferguson 10 – Air Conditioning Control Unit: Evaporator temperature sensor fault - Sensor short-circuited

The system has detected a short circuit in the evaporator temperature sensor or its wiring circuit. As a direct consequence of this fault, the air conditioning control unit automatically turns off the A/C compressor, and cooling is disabled to prevent the evaporator core from freezing over or causing further system damage.

• 7724S
• Interim Tier 4 (2012-2015)
• 7722S
• 7722
• 7615
• 7720S
• 7716
• 7718
• 7726
• 7715
• 7616
• 7618
• 7619
• 7626
• 7624
• 7726S
• 7614
• 7718S
• 7620
• 7719
• 7714
• 7716S
• 7622
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• MF 8600 Series
• 8650
• 8660
• 8670
• 8680
• 8690
• MF 7600 Series
• MF 6700 S Series
• MF 5700 SL Series
• Dyna-4 models
• Dyna-6 models
• Dyna-VT models

1. 1

   Access the HVAC unit and locate the evaporator temperature sensor. Inspect the wiring harness and connectors for any signs of chafing, melting, or exposed copper that could cause a short circuit to ground or to another wire.

2. 2

   Disconnect the sensor and use a digital multimeter to measure the resistance across the sensor's pins. A dead short (near 0 ohms) confirms the sensor has failed internally and must be replaced.

3. 3

   If the sensor tests fine, check the wiring continuity from the sensor connector back to the Air Conditioning control unit to ensure the short circuit is not located within the cab wiring harness.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery isolator switch to prevent electrical spikes.

2. 2

   Access the HVAC Unit

   Remove the necessary cab interior panels (often located in the cab roof or under the seat/dash depending on the specific tractor model) to access the HVAC evaporator housing.

3. 3

   Remove the Faulty Sensor

   Locate the evaporator temperature sensor plugged into the evaporator core. Unplug the electrical connector and carefully pull or unclip the sensor from the evaporator fins.

4. 4

   Install the New Sensor

   Insert the replacement OEM evaporator temperature sensor into the exact same position on the evaporator core to ensure accurate temperature readings.

5. 5

   Reconnect

   Plug the electrical harness back into the sensor, ensuring the connector clicks securely into place.

6. 6

   Reassemble

   Reinstall all HVAC covers and cab interior panels.

7. 7

   Clear Codes and Test

   Reconnect the battery power and turn on the tractor. Clear the fault memory using the instrument panel buttons or the AGCO Electronic Diagnostic Tool (EDT). Turn on the A/C to verify that the compressor engages and cooling is restored.