Massey Ferguson 10.01.27 – AIRCON (Air Conditioning) Module: Issue With Signal To Left Cab Fan Speed Controller (AIRCON)

The electronic signal returning from the left cab fan speed controller (blower motor resistor) is outside of its expected operating range. The system detects a return error, meaning the controller is either receiving an improper voltage signal, has an internal short/open circuit, or the wiring harness is compromised.

• 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
• 5709S
• 6612
• 6613
• 6614
• 6615
• 6616
• 6712S
• 6713S
• 6714S
• 6715S
• 6716S
• 6718S
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714S
• 7719S

1. 1

   Inspect the wiring harness running from the AIRCON module to the left blower motor resistor for chafed wires, melted insulation, or loose connections

2. 2

   Disconnect the plug at the left fan speed controller (resistor) and check for burnt pins or corrosion

3. 3

   Test the left blower motor directly with a 12V source to ensure it spins freely without excessive noise or drag (a failing motor can draw excessive amperage and burn out the resistor)

4. 4

   Verify that the cab fan speed dial/switch on the control panel is sending the correct variable voltage to the AIRCON module

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical shorts.

2. 2

   Access the HVAC Unit

   Remove the inner cab roof liner or exterior roof hatch (depending on the specific tractor model) to access the blower motors and HVAC housing.

3. 3

   Locate the Left Controller

   Identify the left cab fan speed controller (blower motor resistor), which is usually mounted directly into the HVAC ducting to allow airflow to cool it.

4. 4

   Remove the Faulty Component

   Unplug the electrical connector. Remove the mounting screws securing the speed controller to the housing and pull it out.

5. 5

   Install the New Part

   Insert the new fan speed controller, secure the screws, and reconnect the electrical plug. Ensure the connection is tight and apply a small amount of dielectric grease if working in a high-humidity environment.

6. 6

   Reassemble and Test

   Reconnect the battery, turn the key to the ON position, and clear the fault codes using a diagnostic tool. Test the fan at all speed settings to ensure the left blower operates correctly and the code does not return. Reinstall the roof panels.