Massey Ferguson 10.03.05 – AIRCON: Cab Temperature Sensor Open Circuit (AIRCON)

The control module has detected a break in the electrical circuit for the inside cab temperature sensor. An "open circuit" typically indicates that the sensor is unplugged, a wire in the harness is cut or broken, a connector pin is severely corroded, or the sensor itself has failed internally and broken its electrical continuity.

• 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
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714S
• 7719S

1. 1

   Locate the inside cab temperature sensor (typically mounted in the top right side of the fuse panel or behind the headliner/light closest to the center of the cab roof).

2. 2

   Trace the wiring harness from the sensor back toward the AIRCON module. Look for pinched wires, rodent damage, or disconnected plugs.

3. 3

   Unplug the sensor and inspect the connector pins for rust, corrosion, or pushed-out pins that would cause an open circuit.

4. 4

   Set a multimeter to measure resistance (Ohms) and probe the terminals on the sensor itself. If the multimeter reads 'OL' (Open Loop) or infinite resistance, the sensor has failed internally. If it shows a valid resistance reading, the open circuit is in the tractor's wiring harness.

1. 1

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

2. 2

   Remove the interior trim panels or fuse panel cover required to access the cab temperature sensor.

3. 3

   Depress the locking tab on the electrical connector and unplug it from the sensor.

4. 4

   If the diagnostic checks pointed to a wiring issue, repair the broken wire or replace the damaged connector pigtail.

5. 5

   If the sensor is faulty, unclip or unscrew the sensor from its mounting bracket and remove it.

6. 6

   Snap the new OEM cab temperature sensor into place.

7. 7

   Reconnect the electrical harness, ensuring it clicks securely.

8. 8

   Reinstall any removed cab trim or panels.

9. 9

   Reconnect the battery, turn on the ignition, and use a diagnostic scan tool to clear the 10.03.05 fault code.

10. 10

    Run the tractor's HVAC system to verify that the AIRCON module is reading the cab temperature correctly and regulating the climate control.