John Deere 1547 – C00 - Armrest Control Unit: CLIMATRAK Core Temperature Sensor Voltage Too Low

The CLIMATRAK Core Temperature Sensor is reporting a voltage lower than 0.1 VDC to the control unit. This low voltage indicates that the sensor's electrical resistance has dropped below 52 ohms, which the system interprets as an extreme temperature of 356°F (180°C). This condition typically points to a short circuit in the sensor or its wiring harness, compromising the air conditioning system's ability to monitor the evaporator core and prevent icing.

• 9540 WTS
• 9560 WTS
• 9580 WTS
• 9640 WTS
• 9660 WTS
• 9680 WTS
• 9470STS
• 9560STS
• 9570STS
• 9660STS
• 9670STS
• 9760STS
• 9770STS
• 9860STS
• 9870STS
• 9880STS
• 6930
• 7430E
• 7530E
• 7200R-7310R series
• 8225R-8400R series
• 7180-7980 series
• S560
• S690
• T550
• T670
• W540
• W660
• C670
• R450

1. 1

   Visually inspect the CLIMATRAK Core Temperature Sensor and its wiring harness for physical damage, such as chafed, pinched, or melted wires.

2. 2

   Disconnect the sensor's electrical connector and check for corrosion, dirt, or moisture. Clean with electrical contact cleaner if necessary and ensure it is fully seated.

3. 3

   Test for a short to ground (wiring cause): With the sensor disconnected, check for continuity between the signal wire at the harness connector and chassis ground. Any continuity indicates a short circuit in the wiring.

4. 4

   Perform a sensor resistance test (sensor cause): Measure the sensor's resistance using a multimeter. A reading below 52 ohms confirms the fault. Normal operating range is typically between 0 and 700 ohms depending on temperature.

1. 1

   Disconnect power

   Disconnect the negative battery terminal before beginning any repair work for safety.

2. 2

   Locate the sensor

   Access the CLIMATRAK Core Temperature Sensor within the HVAC unit, where it monitors the evaporator and heater core. This may require removing cab panels or components of the HVAC housing.

3. 3

   Repair wiring harness

   If diagnostic checks revealed a short to ground or physical damage, repair the affected wires. Ensure all connections are secure and insulated, or replace the harness section if damage is severe.

4. 4

   Replace the temperature sensor

   If the sensor resistance is below 52 ohms or erratic, disconnect and remove the old sensor from its mounting position in the HVAC housing. Install the new sensor and reconnect the electrical connector.

5. 5

   Reassemble and test

   Reinstall any removed cab panels or HVAC components. Reconnect the battery, start the machine, and operate the CLIMATRAK system to verify the fault code is cleared and the system functions correctly.