Massey Ferguson 10.03.29 – Air Conditioning Module (AIRCON): Issue With Voltage To Air Conditioning Module (AIRCON)

The supply voltage signal reaching the module is higher than the maximum allowed value (overvoltage). To protect the circuitry, the control unit is automatically deactivated, which will cause the cab air conditioning and climate control functions to stop working.

• 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
• 4707
• 4708
• 4709
• 4710
• 5600 Series
• 5700SL Series
• 5608–5613
• 5710SL–5713SL
• 7600 Series
• 7700 Series
• 7614–7626
• 7714–7726
• 8600 Series

1. 1

   Test system charging voltage: Start the tractor and measure voltage across the battery terminals (should be 13.5V-14.5V; above 15V indicates an overcharging alternator).

2. 2

   Check module supply voltage: Back-probe the power supply pins at the back of the AIRCON module and compare this reading to the battery voltage.

3. 3

   Inspect wiring harness: Check the cab wiring harness for chafing or melting that could cause a short-to-power.

4. 4

   Check grounds: Verify that the cab ground strap and the AIRCON module ground wires are clean and tight.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable to prevent electrical shorts during repair.

2. 2

   Address the Alternator (If Overcharging)

   If your diagnostic checks revealed system-wide overvoltage, remove the drive belt and replace the alternator (or just the voltage regulator, if serviceable on your specific engine).

3. 3

   Repair Wiring (If Shorted)

   If the alternator is fine but the module connector shows overvoltage, trace the harness back to the fuse panel. Repair any damaged wires using heat-shrink butt connectors and re-loom the harness.

4. 4

   Replace the AIRCON Module (If Internally Faulty)

   If the supply voltage at the connector is perfectly normal (approx. 12-14V) but the module still throws code 10.03.29 and shuts down, the module's internal voltage sensing circuit has failed. Remove the trim surrounding the climate control panel, unscrew the retaining screws holding the module in the console, disconnect the electrical pigtails from the rear of the unit, plug in the new OEM control module and reinstall the trim.

5. 5

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a diagnostic scan tool to clear the inactive fault codes. Start the tractor and test the A/C blower and compressor engagement.