New Holland 16120 – Climate Control Module: Fan Speed Potentiometer Power Supply Circuit Fault

The fault code indicates a problem with the power supply circuit of the fan speed potentiometer, specifically an open circuit or a short to power. The control module has detected an abnormal voltage reading, which results in improper operation or total failure of the in-cab HVAC blower fan speed control system.

• T7 Series
• TM Series
• T6000 Series
• T7000 Series
• T4040
• TN Series
• BR740
• 8770A
• CR920

1. 1

   Visually inspect the wiring harness connected to the fan speed control knob (potentiometer) for chafing, cuts, or melted insulation

2. 2

   Check the connectors at the potentiometer and the corresponding control module for corrosion, bent pins, or loose connections

3. 3

   Verify the vehicle's battery is fully charged and the charging system is functioning correctly, as electronics can be sensitive to voltage drops

4. 4

   Test the potentiometer with a multimeter by measuring resistance across its terminals while turning the knob (an abrupt jump, infinite resistance, or zero resistance indicates a faulty potentiometer)

5. 5

   Check for open circuits by testing continuity on the signal and ground wires between the potentiometer's connector and the control module's connector

6. 6

   Check for shorts to power by turning the ignition on (engine off) and testing the signal wire at the potentiometer's connector for unwanted voltage

1. 1

   Disconnect power

   Disconnect the vehicle's battery before starting any electrical repairs to ensure safety.

2. 2

   Access the component

   Remove any dash panels or covers necessary to gain access to the fan speed control potentiometer.

3. 3

   Repair wiring

   If diagnostic checks revealed an open circuit or a short to power, repair or replace the damaged section of the wiring harness. Ensure all connections are secure and properly insulated.

4. 4

   Replace the potentiometer

   If the potentiometer failed the resistance test, replace it with the correct OEM part for your specific machine.

5. 5

   Reassemble and test

   Reconnect the battery and reassemble the dash panels. Turn the ignition on and test the functionality of the fan speed control to ensure the fault has been resolved.