Massey Ferguson 10.02.32 – AIRCON: Issue With Signal To Right Cab Fan Speed Controller (AIRCON)

Indicates an electrical fault—such as an open circuit, short circuit, or out-of-range voltage—between the climate control module and the blower motor resistor (speed controller) on the right side of the cab. The most common symptom of this failure is the right cab fan only working on its highest speed setting or failing to blow air entirely.

• 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
• 4300 Series
• 4707
• 4708
• 4709
• 4710
• 5400 Series
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 6400 Series
• 6600 Series
• 6700 Series
• 7400 Series
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8400 Series

1. 1

   Verify the symptom by testing the cab fan on all speed settings. If it only blows on 'High' or doesn't blow at all, the resistor is likely the culprit.

2. 2

   Inspect the wiring harness leading to the right cab roof area for breaks, chafing, or melted wires.

3. 3

   Unplug the connector at the blower motor resistor. Inspect the pins for corrosion caused by humidity or signs of melting due to electrical resistance heat.

4. 4

   Use a multimeter to verify that proper voltage is reaching the resistor from the fan speed switch. If there is no power reaching the resistor, the issue may lie with the Fan Speed Switch on the control panel.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery before starting any electrical work. Allow the HVAC system to cool down if the fan has been running, as the resistor gets very hot during operation.

2. 2

   Access the Resistor

   The right cab fan speed controller (resistor) is located in the cab roof. You will need to lift the cab roof or remove the large rectangular access cover near the right-side blower motor (right front corner of the cab roof).

3. 3

   Remove the Old Controller

   Disconnect the plug-in electrical connector. Remove the mounting screws holding the resistor in place and pull it out.

4. 4

   Clean the Area

   Clean the mounting area and ensure there is no debris blocking the ventilation around the resistor, as poor airflow will cause the new resistor to overheat and fail prematurely.

5. 5

   Install the New Part

   Insert the new blower motor resistor, secure it with the mounting screws, and plug the electrical connector back in.

6. 6

   Reassemble and Test

   Reinstall the cab roof cover, reconnect the battery, and test the fan on all speed settings to ensure the fault code clears and airflow is restored.