Massey Ferguson AC08 – Air Conditioning Control Module: Outside Temperature Sensor Short Circuit

The system has detected a short circuit in the wiring or internally within the outside ambient air temperature sensor (X358), which prevents the automatic climate control system from accurately reading the exterior temperature and disrupts automatic cabin temperature regulation.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• MF 7600 Series (7614 to 7626)
• MF 8600 Series (8670, 8690)
• MF 8400 Series (8450, 8460, 8470, 8480)
• MF 8100 Series (8160, 8180)
• Tractors equipped with Dyna-4 and Dyna-6 transmissions

1. 1

   Locate the outside temperature sensor (X358), typically mounted near the front grille, under the cab roof overhang, or near the fresh air intake.

2. 2

   Inspect the wiring harness leading to the sensor for any visible chafing, pinched wires, or melted insulation that could cause a short to ground or a short between the two sensor wires.

3. 3

   Disconnect the sensor and use a multimeter to measure its internal resistance. If the resistance reads at or near zero ohms, the sensor is internally short-circuited.

4. 4

   Test the circuit by turning the key to the ON position with the sensor disconnected. If the fault code changes from AC08 (Short Circuit) to AC07 (Sensor Open), the wiring is likely intact, confirming the sensor itself is the culprit.

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical spikes during repair.

2. 2

   Remove the Faulty Sensor

   Disconnect the oval 2-pin electrical connector from the outside temperature sensor. Unclip or unbolt the sensor from its mounting bracket.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a short in the harness rather than the sensor, splice and heat-shrink the damaged wires, or replace the damaged section of the harness.

4. 4

   Install the New Sensor

   Snap or bolt the new ambient temperature sensor into the factory mounting location.

5. 5

   Reconnect

   Plug the electrical connector back into the sensor, ensuring the weather seal is seated properly. Reconnect the battery.

6. 6

   Clear Codes

   Turn the ignition on and verify that the AC08 code is no longer active (or clear it via the tractor's diagnostic terminal/instrument panel). Test the air conditioning system to ensure automatic climate control resumes normal operation.