Massey Ferguson 10.00.31 – AIRCON: Issue With Signal To Left Cab Fan Speed Controller (AIRCON)

Fan speed controller no. 1 return error. The return signal from the left cab fan speed controller (or fan speed potentiometer) is outside of its expected operating range.

• 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
• 5700 Series
• 5608–5613
• 5710SL–5713SL
• 6700 Series
• 7600 Series
• 7700 Series
• 7614–7626
• 7714–7726
• 8600 Series

1. 1

   Inspect the wiring harness and connector X445 between the AIRCON control module and the left cab fan speed controller for corrosion, backed-out pins, or moisture

2. 2

   Verify the voltage supply to the main air conditioning control module at the blue connector X439 and yellow connector X440

3. 3

   Test the fan speed potentiometer signal with a multi-meter to ensure it is not open, shorted to ground, or out of range

1. 1

   Access the Components

   Gain access to the HVAC blower assembly and the AIRCON control module, typically located in the cab roof or under the cab depending on the specific tractor model.

2. 2

   Disconnect and Inspect

   Disconnect connector X445 at the left cab fan speed controller. Inspect the terminals for signs of arcing or melting, which is common in high-draw blower motor circuits.

3. 3

   Test Continuity

   Perform a continuity test on the signal wire running from the fan speed controller back to the AIRCON module.

4. 4

   Repair Wiring

   If a break or short is found in the harness, repair the wiring using appropriate weatherproof splices.

5. 5

   Replace the Controller

   If the wiring harness tests good and the main AIRCON module is receiving proper voltage, the internal circuitry of the left fan speed controller has failed. Remove the mounting screws, extract the faulty controller, and install the replacement module.

6. 6

   Clear Codes and Test

   Reconnect all harnesses. Use the AGCO Electronic Diagnostic Tool (EDT) to clear the 10.00.31 fault code. Run the HVAC system through all fan speeds to verify the left blower motor responds correctly.