John Deere 1552 – Cornerpost Control Unit: Climatrak Temperature Setpoint Adjust Voltage Too Low

The fault code 1552 is triggered when the Climatrak temperature setpoint adjust voltage drops below the minimum threshold of 0.5 VDC. This low voltage reading indicates an open circuit, a shorted circuit, or a failure within the temperature control device itself. The component responsible is a potentiometer that functions as a variable resistor to inform the control unit of the desired temperature setting.

• 9450
• 9550
• 9650
• 9540 WTS
• 9560 WTS
• 9580 WTS
• 9640 WTS
• 9660 WTS
• 9680 WTS
• 9560 STS
• 9660 STS
• 9760 STS
• 9860 STS
• 9670 STS
• 9770 STS

1. 1

   Visually inspect the wiring harness connected to the Climatrak control panel for frayed wires, loose connections, or corrosion.

2. 2

   Disconnect the temperature selector dial (potentiometer) from the circuit to avoid interference.

3. 3

   Measure the total resistance between the two outer terminals of the potentiometer using a multimeter to ensure it matches the rated value.

4. 4

   Test the potentiometer wiper by connecting one multimeter probe to the center terminal and the other to an outer terminal. Slowly rotate the dial through its full range; the resistance should change smoothly without sudden jumps or dropouts. Repeat this test using the other outer terminal.

1. 1

   Access the control panel

   Disassemble the Climatrak control panel in the cab to access the temperature control potentiometer.

2. 2

   Test the potentiometer

   Perform the resistance sweep tests outlined in the diagnostic checks to confirm if the potentiometer is the source of the fault.

3. 3

   Check wiring

   If the potentiometer tests as functional, check the wiring between the potentiometer and the Cornerpost Control Unit for continuity and for shorts to ground or power.

4. 4

   Replace the potentiometer

   If the potentiometer is found to be faulty (erratic or non-changing resistance readings), replace it with a new unit.

5. 5

   Calibrate the system

   After replacing the potentiometer, perform a Climatrak calibration. This is typically accessed through the combine's diagnostic address menu and initiated via the cornerpost display.