Massey Ferguson 29 – Air Conditioning Module (AIRCON): Issue With Voltage To Air Conditioning Module (AIRCON)

The tractor's electronic control system has detected that the voltage being supplied to the HVAC/Air Conditioning control unit is outside of the expected operating parameters. This is typically caused by an open circuit, a short circuit, a blown fuse, or a failing voltage load protection module.

• 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

1. 1

   System Voltage Check: Use a multimeter to test the battery and alternator output. If the alternator regulator is failing (outputting too high or too low voltage), it will trigger module voltage codes.

2. 2

   Fuse Inspection: Check the cab power and HVAC fuses in the main fuse panel (e.g., F52, F53, or the specific A/C fuse for your model).

3. 3

   Connector Inspection: Locate the Air Conditioning Module (often located under the cab floor or within the cab roof/dash depending on the model). Inspect its main electrical connectors (noted as blue and yellow connectors on some high-horsepower models) for moisture ingress, corrosion, or backed-out pins.

4. 4

   Wiring Harness Test: Perform a voltage drop test on the power supply wire leading to the AIRCON module. Verify that the module's ground connection to the chassis is clean and tight.

1. 1

   Disconnect Power

   Turn off the tractor ignition and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Repair Wiring/Fuses

   If a blown fuse is found, replace it. If the wiring harness shows chafing or the connector pins are corroded, clean the pins with electrical contact cleaner and repair the damaged wire sections.

3. 3

   Replace Voltage Load Protection Module (If Applicable)

   On some Massey Ferguson models, a failing voltage load protection module will cut power to cab accessories. If this module tests faulty, replace it.

4. 4

   Replace the AIRCON Module

   If the wiring, grounds, and fuses all test good (meaning the module is receiving proper voltage but still logging an internal voltage fault), the Air Conditioning Module itself has failed and must be replaced.

5. 5

   Reassembly & Clearing Codes

   Reconnect the battery. Use a dealer EST (Electronic Service Tool) or compatible diagnostic scanner to clear the 10.X.28 / 10.X.29 fault codes.

6. 6

   Verification

   Start the tractor, turn on the A/C, and verify that the blower motors and compressor engage without the code returning.