Massey Ferguson 10.03.30 – AIRCON: Issue With Signal To Right Cab Fan Speed Controller (AIRCON)

The climate control system has detected a signal fault (such as an open circuit, short circuit, or out-of-range voltage) in the circuit that controls the right-side cab blower motor resistor (speed controller).

• 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
• 4707
• 4708
• 4709
• 4710
• 5600 Series
• 5608-5613
• 5700 Series
• 5710SL-5713SL
• 7600 Series
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7700 Series
• 7714-7726 (including 'S' models)

1. 1

   Test the right cab fan operation. If the fan only blows on the highest speed setting, is stuck on one speed, or does not blow at all, the blower motor resistor has almost certainly failed.

2. 2

   Inspect the wiring harness and the connector plugging into the right blower motor resistor for melting, burning, or corrosion caused by cab humidity and heat.

3. 3

   Use a multimeter to verify that the AIRCON module is sending the proper voltage signal to the resistor connector.

4. 4

   Test the right blower motor itself for excessive amperage draw. A failing blower motor with worn bearings will draw excessive amperage and quickly burn out a brand-new replacement resistor.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical shorts.

2. 2

   Access the HVAC Unit

   On most Massey Ferguson tractors, the HVAC assembly is located in the cab roof. Lift the cab roof or remove the screws securing the large rectangular access cover.

3. 3

   Locate the Resistor

   Find the right cab fan speed controller (blower motor resistor). It is typically mounted right next to the right blower motor in the front right corner of the cab roof. It is mounted directly in the airflow path to keep it cool.

4. 4

   Remove the Faulty Part

   Unplug the electrical connector from the resistor. Remove the mounting screws and pull the resistor out.

5. 5

   Clean the Area

   Ensure there is no dust or debris blocking the ventilation path around the mounting area, as restricted airflow causes resistors to overheat.

6. 6

   Install the New Part

   Insert the new resistor, secure it with the mounting screws, and plug in the electrical connector (ensure it clicks tightly into place).

7. 7

   Reassembly

   Reinstall the cab roof access cover.

8. 8

   Test

   Reconnect the battery and test the climate control system to ensure the right fan operates smoothly across all speed settings.