Standard Coolant - Coolant Level Sensor – How it Works and Troubleshooting Guide

How it Works

The coolant level sensor uses a float assembly inside the coolant tank to detect the coolant level. As the float raises or lowers, it turns a potentiometer. The control reads the voltage and displays the coolant level on the MEMORY or CURRENT COMMANDS pages.

Symptom Check Possible Cause Corrective Action Section
The coolant level sensor displays an incorrect coolant level. Coolant Level Sensor The sensor is damaged, or the float cannot move. Check all of the wires and clear chips blocking the float. 1
Cable The cable is unplugged or damaged. Make sure that the cable is securely connected and is not damaged.

Section 1

Symptom: The coolant level sensor displays an incorrect coolant level.

Possible Cause: The sensor is damaged, or the float cannot move.

Corrective Action:

If your coolant level sensor does not display the correct level on the screen, look in the coolant tank to make sure a chip build-up does not block the float from moving freely.

Make sure the coolant level sensor operates correctly:

  • Press MEMORY. The upper-right corner of the screen will show the coolant level.
  • Remove the level sensor from the tank and move the float to the maximum travel at both ends. The coolant level indicator on the screen should move at a slow pace. It takes approximately (1) minute to move from empty [2] to full [1] on the screen, but it starts to move immediately.
  • If the coolant level sensor does not operate correctly, unplug the coolant level sensor from the machine. Remove the cover to access the wires of the variable resistor.
  • Measure the resistance across the white and black wires [3/4] when the float is up [5] and when it is down [6]. The resistance should be approximately 371 Ohms when the float is up and 286 Ohms when it is down.
  • Make sure that the coolant level sensor RJ12 cable [2] or M12 cable [1] is securely connected, and is not damaged.
  • If the coolant level sensor continues to read incorrectly, and you have completed the troubleshooting instructions, replace the sensor.

Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.