Massey Ferguson 10.03.28 – Air Conditioning Module (AIRCON): Issue With Voltage To Air Conditioning Module (AIRCON)

Failure due to undervoltage. The supply voltage signal reaching the module has dropped below the minimum required operating threshold. When this code is active, the control unit typically defaults to operating in a degraded mode to protect the system.

• 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
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8650
• 8660
• 8670
• 8680
• 8690

1. 1

   Check battery voltage with a multimeter (should read around 12.6V when the engine is off) to rule out low system voltage.

2. 2

   Test alternator output voltage while the engine is running (should be around 13.5V - 14.5V) to ensure proper charging.

3. 3

   Inspect the cab fuse box for any blown fuses related to the air conditioning system or cab power supply.

4. 4

   Inspect the wiring harness leading to the Air Conditioning Module for chafed wires, loose connections, or corrosion at the connectors.

5. 5

   Ensure the ground connections for the cab and the air conditioning module (e.g., X438 - Earth) are clean and secure.

1. 1

   Safety First

   Turn off the tractor, remove the key, and disconnect the negative battery terminal.

2. 2

   Clean Power Sources

   Clean the battery terminals with a wire brush and baking soda solution to ensure a solid connection. Reconnect and tighten.

3. 3

   Test Module Supply Voltage

   Disconnect the connector at the Air Conditioning Module (often a blue or yellow connector, e.g., X439/X440 on the 8600 series). Reconnect the battery, turn the key to the ON position, and use a multimeter to measure the voltage at the power supply pins on the connector. It should match the battery voltage.

4. 4

   Repair Wiring

   If the voltage at the connector is lower than the battery voltage, trace the wiring back to the fuse panel. Repair any broken, corroded, or exposed wires using proper automotive wiring repair techniques (solder and heat shrink).

5. 5

   Replace Module

   If the supply voltage at the connector is correct (above the minimum threshold) but the module still logs the undervoltage fault, the internal circuitry of the Air Conditioning Module has likely failed. The module must be replaced.

6. 6

   Clear Codes

   After repairs, use the tractor's Dash Control Center or a compatible diagnostic tool to clear the fault codes and verify the air conditioning operates correctly.