Massey Ferguson 5 – AIRCON: Cab Temperature Sensor Open Circuit (AIRCON)

The climate control unit is registering a voltage in the cab temperature sensor circuit that is too high (typically above 4.86V). This condition occurs when the sensor is completely disconnected, the signal wire is broken/cut, or the sensor has failed internally and has an open circuit.

• 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
• 9695
• 9795

1. 1

   Locate the inside cab temperature sensor (usually mounted in the top right side of the fuse panel, in the roof headliner, or below the operator's seat)

2. 2

   Visually inspect the sensor's electrical connector for loose pins, corrosion, or moisture, and check the wiring harness for chafing, cuts, or pinch points

3. 3

   Perform a sensor resistance test by unplugging the sensor and measuring resistance across its terminals (an 'OL' or infinite reading indicates internal failure)

4. 4

   Perform a harness continuity test between the sensor connector and the ATC/AIRCON controller pins to check for an open wire

1. 1

   Turn off the machine's ignition and disconnect the battery ground cable to prevent electrical shorts.

2. 2

   Remove the necessary interior cab trim panels to access the cab temperature sensor.

3. 3

   Disconnect the wiring harness from the faulty sensor.

4. 4

   If wiring is damaged: Splice and repair the broken wire using heat-shrink connectors, ensuring a weather-tight seal.

5. 5

   If the sensor is faulty: Unclip or unscrew the old sensor from its mounting bracket and install the new OEM replacement.

6. 6

   Reconnect the sensor harness and reinstall the cab trim panels.

7. 7

   Reconnect the battery ground.

8. 8

   Turn on the ignition, clear the fault codes from the AIRCON module using the diagnostic interface, and run the A/C system to verify the code does not return.