Massey Ferguson 10.X.28 – Air Conditioning Module (AIRCON): Issue With Voltage To Air Conditioning Module (AIRCON)

Failure due to undervoltage. The supply signal (voltage) reaching the module is lower than the minimum required value. When this code is triggered, the air conditioning control unit is forced to operate in a degraded (fail-safe) mode.

• 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
• 8600 Series
• 8650
• 8660
• 8670
• 8680
• 8690
• 4700 Series
• 4707
• 4708
• 4709
• 4710
• 5600 Series
• 5700 Series
• 5608-5613
• 5710SL-5713SL
• 7600 Series
• 7700 Series
• 7614-7626
• 7714-7726

1. 1

   Check the battery voltage using a multimeter; a fully charged battery should read around 12.6V. Verify that the alternator is outputting the correct voltage, as low system voltage will trigger this code.

2. 2

   Check the wiring harness leading to the Air Conditioning Module and the compressor coil. Look for chafed wires, loose grounds, or corroded pins at the module connectors (often color-coded, such as the blue and yellow connectors on the 8600 series).

3. 3

   Use a multimeter to ensure proper voltage is reaching the module and the compressor coil under load.

4. 4

   Inspect the cab power supply fuses and the A/C relays (e.g., fan relays, clutch relays) to ensure they are not burnt out or causing a voltage drop.

1. 1

   Disconnect Power

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

2. 2

   Access the Module/Wiring

   Remove the necessary cab trim panels to access the Air Conditioning Module and its wiring harness.

3. 3

   Repair Wiring/Connectors

   If the diagnostic checks revealed damaged wiring or corroded connectors, splice in new wiring or replace the damaged connector pins. Ensure all ground connections to the cab chassis are clean and tight.

4. 4

   Replace Faulty Relays

   If a relay is found to be dropping voltage (a common issue with A/C clutch circuits), replace it. (Some older/crossover models utilize a Low Voltage Clutch Coil Protection Kit to prevent this exact issue).

5. 5

   Replace the Module (if necessary)

   If the wiring, relays, and battery voltage are all perfect but the module still reads an undervoltage fault, the module itself has an internal fault. Unplug the connectors, unbolt the module, and install the OEM replacement.

6. 6

   Reassemble and Clear Codes

   Reconnect the battery, turn on the ignition, and use the tractor's diagnostic interface to clear the 10.X.28 fault code. Test the A/C system to ensure the compressor engages and the fan operates correctly.