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

Failure due to undervoltage, meaning the electrical supply signal reaching the module is lower than the minimum required operating value.

• 7724S
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 7720S
• 7716
• 7718
• 7726
• 7715
• 7616
• 7618
• 7619
• 7626
• 7726S
• 7624
• 7614
• 7718S
• 7620
• 7719
• 7714
• 7716S
• 7622
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 7714S
• 7719S
• 8600 Series

1. 1

   Test battery and alternator to ensure the tractor's base system voltage is healthy, as a weak battery or failing alternator can trigger undervoltage codes.

2. 2

   Inspect the cab fuse box for blown fuses or sticking relays that supply power to the AIRCON module.

3. 3

   Inspect the wiring harness leading up to the cab roof/climate control unit for rub points, pinched wires, or damaged grounds causing a voltage drop.

4. 4

   Disconnect the harness at the Air Conditioning Module and use a multimeter to verify that the proper operating voltage (12V) is reaching the connector pins when the key is in the ON position.

1. 1

   Disconnect Power

   Always disconnect the negative battery terminal before servicing cab electronics to prevent short circuits.

2. 2

   Access the Module

   Remove the interior cab roof panel or side console trim (depending on the specific tractor model) to access the Air Conditioning Module and its wiring.

3. 3

   Clean and Reseat Connectors

   If the multimeter test showed good voltage, the issue may be a loose or corroded pin. Clean the module's blue and yellow connectors with electrical contact cleaner and reseat them firmly.

4. 4

   Repair Harness/Fuses

   If voltage was low or missing during diagnostics, repair the damaged section of the wiring harness or replace the faulty power relay/fuse.

5. 5

   Replace the Module

   If the wiring, fuses, and relays are all supplying the correct voltage to the connector, but the code persists, the Air Conditioning Module has an internal fault and must be replaced.

6. 6

   Clear Codes

   Reconnect the battery, turn the ignition on, and use a diagnostic tool to clear the fault codes and test the A/C operation.