Massey Ferguson AC17 – Air Conditioning Panel Module (AIRCON): Air Conditioning Panel Module Internal Issue With Fan Speed Dial

The climate control system is detecting an implausible signal, an open circuit, or a short circuit from the potentiometer (the variable resistor) that controls the cab's blower fan speed, indicating that the module cannot read the resistance properly.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 4707
• 4708
• 4709
• 4710
• 5710SL
• 5711SL
• 5712SL
• 5713SL

1. 1

   Physical Dial Inspection: Check the fan speed dial for physical damage, looseness, or lack of physical resistance when turning. A broken internal plastic shaft can cause the potentiometer to stop turning.

2. 2

   Connector Check: Access the rear of the AC control panel and locate the fan potentiometer connector. Inspect it for backed-out pins, corrosion, or loose wiring.

3. 3

   Potentiometer Sweep Test: Using a digital multimeter, measure the resistance across the fan speed dial's potentiometer pins while slowly turning the dial. The resistance should change smoothly. If the multimeter reads 'OL' (open loop) or shows erratic jumps/dead spots, the potentiometer track is internally damaged.

4. 4

   Wiring Harness Continuity: Check the wiring harness between the fan speed dial connector and the main AC module board for continuity and ensure there are no shorts to ground.

1. 1

   Disconnect Power

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

2. 2

   Remove Trim

   Carefully pry away the plastic cab trim/bezel surrounding the climate control panel. Use non-marring plastic trim tools to avoid damaging the cab interior.

3. 3

   Extract the Module

   Remove the retaining screws (usually Torx or Phillips) securing the AC control panel to the cab console.

4. 4

   Disconnect Harnesses

   Pull the AC module forward gently. Disconnect the main electrical harness and the specific fan potentiometer connector from the rear of the unit.

5. 5

   Install New Module

   Plug the electrical connectors into the replacement AC control panel. Ensure the locking tabs click into place.

6. 6

   Reassembly

   Seat the new panel into the console, install the retaining screws, and snap the trim bezel back into place.

7. 7

   Test and Clear Codes

   Reconnect the battery. Turn the ignition on and test the fan speed dial through all speed settings. Use a diagnostic scan tool (or the tractor's onboard diagnostic menu) to clear the AC17 fault code.