John Deere 1547 – ACU: CLIMATRAK Core Temperature Sensor Voltage Too High

The CLIMATRAK Core Temperature Sensor is reporting a voltage higher than 4.47 VDC to the Armrest Control Unit (ACU). This indicates that the sensor resistance is greater than 101KΩ, which the system interprets as an extremely cold temperature of -4°F or -20°C. This high voltage reading typically signifies an open circuit, a poor connection in the wiring, or a failed sensor within the cab's automatic temperature control system.

• 9540 WTS
• 9560 WTS
• 9580 WTS
• 9640 WTS
• 9660 WTS
• 9680 WTS
• 9660 CTS
• 9560 STS
• 9660 STS
• 9760 STS
• 9860 STS
• 9770 STS
• 9650 STS
• 9750 STS

1. 1

   Retrieve and document all active and stored fault codes using the diagnostic display to identify any related issues.

2. 2

   Visually inspect the wiring harness and connectors leading to the CLIMATRAK Core Temperature Sensor for chafing, breaks, or corrosion. Ensure the connector is clean and securely seated.

3. 3

   Unplug the sensor with the key on. If a low voltage code for the same sensor appears (e.g., 1547.04), it strongly suggests the wiring to the sensor is intact and the sensor itself is faulty.

4. 4

   Test the sensor's resistance using a digital multimeter. A reading of 'open' or infinite resistance confirms a failed sensor.

1. 1

   Safety First

   Park the machine on a level surface, shut down the engine, and remove the key.

2. 2

   Access the HVAC Unit

   Remove the instructional (buddy) seat to gain access to the CLIMATRAK system's components.

3. 3

   Locate the Sensor

   Identify the core temperature sensor, which will be a probe inserted into the evaporator core housing.

4. 4

   Disconnect and Remove

   Carefully disconnect the electrical connector from the sensor. Then, withdraw the old sensor probe from the evaporator core.

5. 5

   Install the New Sensor

   Insert the new temperature sensor probe into the evaporator core and securely fasten the electrical connector.

6. 6

   Reassemble

   Reinstall the instructional seat and any other removed components.

7. 7

   Clear Fault Codes

   Start the machine and access the diagnostic system to clear the 1547 fault code.

8. 8

   Verify the Repair

   Operate the CLIMATRAK system to ensure it is functioning correctly and that the fault code does not reappear.