Massey Ferguson 10.03.01 – AIRCON: Air Conditioning Vent Temperature Sensor Open Circuit

The climate control system has detected an open circuit in the vent/evaporator temperature sensor circuit, indicating a broken wire, a disconnected plug, or an internal thermistor failure reading infinite resistance. The air conditioning compressor is disabled to prevent evaporator freeze-up.

• 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
• 4700 series
• 5700 series
• 6700 series
• 4707
• 4710
• 6713
• 5400 series
• 5600 series
• 6400 series
• 7400 series
• 7600 series
• 7700 series
• 8400 series
• 8600 series
• 8700 series
• 5610
• 7624
• 8690
• 8737

1. 1

   Visual Inspection: Locate the vent/evaporator temperature sensor and inspect the wiring harness for chafing, rodent damage, or pinched wires. Ensure the connector is securely plugged in and free of corrosion.

2. 2

   Voltage Check: Disconnect the sensor and turn the ignition key to the ON position. Use a multimeter to verify that the reference voltage (typically 5V or 12V depending on the model year) and a good ground are present at the harness connector.

3. 3

   Sensor Resistance Test: Measure the resistance across the two pins of the temperature sensor itself. If the multimeter reads 'OL' (Open Loop) or infinite resistance, the sensor has internally failed and must be replaced.

4. 4

   Continuity Test: If the sensor tests within normal resistance ranges, check the continuity of the wiring harness from the sensor connector back to the AIRCON module pins to locate the break in the circuit.

1. 1

   Locate the Sensor

   The vent/evaporator temperature sensor is typically located inserted into the HVAC ducting or directly into the evaporator housing. Depending on your specific tractor model, this will either be behind the dashboard/steering console or inside the cab roof assembly.

2. 2

   Disconnect Power

   Turn off the tractor and disconnect the battery ground cable to prevent electrical shorts.

3. 3

   Remove the Sensor

   Unplug the electrical connector from the sensor. Gently twist and pull (or unclip) the faulty temperature sensor from the HVAC housing.

4. 4

   Install the New Sensor

   Insert the replacement sensor into the housing, ensuring it is seated securely so air does not leak around it.

5. 5

   Reconnect

   Plug the electrical connector back into the sensor and reconnect the battery.

6. 6

   Clear Codes

   Turn the ignition on. The system may self-clear the code once a valid resistance value is detected. If the code remains stored as active, use the AGCO Electronic Diagnostic Tool (EDT) to clear the fault history and verify that the A/C compressor engages.