Massey Ferguson 10.X.29 – AIRCON Module: Issue With Voltage To Air Conditioning Module (AIRCON) - Overvoltage

The supply voltage reaching the AIRCON module is higher than the maximum allowed value, which causes the control unit to deactivate itself to prevent internal circuit damage.

• 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
• 5600 series
• 5700 series
• 6700 series
• 7600 series
• 7700 series
• 8600 series
• 9500 series
• 9520
• 9540
• 9600 series
• 9695
• 9700 series
• 9795
• 9800 series

1. 1

   Perform a system voltage test: measure battery voltage with the engine running. Readings over 14.5V - 15V indicate an alternator voltage regulator failure (overvoltage cause).

2. 2

   Inspect the wiring harness leading to the cab's climate control panel for any shorts to power.

3. 3

   Disconnect the AIRCON module and test the power supply pins on the harness side to verify the exact voltage reaching the module.

1. 1

   Resolve the Overvoltage Source

   If the alternator is overcharging, replace the alternator or its internal voltage regulator. Do not simply replace the AIRCON module first, as the new module will be subjected to the same damaging voltage spikes.

2. 2

   Repair Wiring

   If the alternator is functioning normally, trace and repair any short-to-power faults in the cab wiring harness.

3. 3

   Assess the AIRCON Module

   If the tractor's charging system is fixed but the panel remains unresponsive or still throws the code, the internal circuitry of the module has likely burned out.

4. 4

   Replace or Repair the Module

   Remove the climate control panel from the cab console/roof. You can either install a new OEM replacement or send the damaged unit to an agricultural electronics repair specialist.

5. 5

   Clear Codes

   Reconnect the system, turn the key to the ON position, and clear the stored fault codes. Test the A/C blower and temperature controls for proper operation.