Massey Ferguson 10.00.33 – AIRCON: Air Vent Circulation Flap Position Sensor Voltage Issue

The system has detected that the voltage signal coming from the air vent circulation flap position sensor is outside of its expected operating range, typically indicating a wiring fault, a failed potentiometer inside the actuator, or a physically jammed flap.

• 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
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• MF 6700 S
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8600 series tractors

1. 1

   Check for physical binding of the circulation flap by accessing the HVAC unit and manually inspecting for debris or a broken hinge.

2. 2

   Inspect the wiring harness and connectors between the AIRCON module and the circulation flap actuator for chafed wires, broken connections, or corroded pins.

3. 3

   Verify the sensor is receiving the correct 5V reference voltage and has a solid ground, then check the signal wire for continuity back to the AIRCON module.

4. 4

   Use the AGCO Electronic Diagnostic Tool (EDT) to monitor live voltage data of the flap position sensor while commanding the recirculation on and off to check for internal shorts.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical shorts during the repair.

2. 2

   Access the HVAC Assembly

   Remove the necessary cab interior panels or roof liner to access the main HVAC distribution box.

3. 3

   Locate the Actuator

   Identify the air vent circulation flap actuator (the small electric motor assembly attached to the side of the air distribution box).

4. 4

   Remove the Faulty Unit

   Disconnect the electrical wiring pigtail from the actuator. Remove the mounting screws holding the actuator to the HVAC housing and carefully pull it away, ensuring you do not break the plastic linkage on the flap door.

5. 5

   Install the New Actuator

   Align the new actuator's drive spline with the flap linkage. Secure it with the mounting screws.

6. 6

   Reconnect and Reassemble

   Plug the electrical connector back in. Reassemble the cab panels/roof liner.

7. 7

   Recalibrate

   Reconnect the battery. Turn the ignition on and use the AGCO EDT (or the tractor's onboard diagnostic menu, if equipped) to clear the 10.00.33 fault code. Run an HVAC self-test or calibration procedure so the AIRCON module can learn the new sensor's end-stop voltage limits.