Introduction
A dishwasher float switch is a safety device that helps control how much water enters the dishwasher during a cycle.
It works together with the dishwasher float to monitor the water level inside the tub. When the water reaches the correct level, the float rises and activates the float switch. This signals the dishwasher to stop filling with water.
Without a functioning float switch, the dishwasher could overfill or fail to fill properly.
How the Dishwasher Float System Works
The float switch is part of a simple water level control system.
The system has two main components:
• The float inside the dishwasher tub
• The float switch located underneath the tub
As the dishwasher fills with water, the float rises. When the float reaches a certain height, it presses a lever connected to the float switch underneath the dishwasher.
This triggers the switch and sends a signal to the control board to stop the water inlet valve.
Once the fill cycle stops, the dishwasher begins washing.
If the float drops again during draining, the switch resets and the system can allow water to enter again during the next cycle.
Why the Float Switch Is Important
The float switch prevents one of the most common dishwasher problems: overfilling.
If the dishwasher continues filling without stopping, water can leak out of the tub and cause damage to flooring or cabinets.
The float switch protects against this by cutting power to the water inlet valve when the correct level is reached.
It also helps the dishwasher maintain the proper water level needed for effective cleaning.
What Happens if the Float Switch Fails
If the float switch stops working correctly, the dishwasher may behave in several different ways.
Common problems include:
• Dishwasher does not fill with water
• Dishwasher stops filling too early
• Dishwasher will not start a wash cycle
• Dishwasher continues filling too long
• Dishwasher displays fill or water errors
Sometimes the float switch itself is not broken, but the float becomes stuck due to debris or mineral buildup.
Float Switch vs Dishwasher Float
The float and float switch are two different parts that work together.
The float is the visible plastic component inside the dishwasher tub. It moves up and down with the water level.
The float switch is located underneath the dishwasher and is activated when the float moves upward.
If the float cannot move freely, the switch may remain engaged and prevent the dishwasher from filling.
How to Tell if the Float Switch Is Working
In many cases, the float switch can be checked without removing major components.
Simple checks include:
• Gently lifting the float inside the dishwasher
• Listening for a small clicking sound
• Checking whether the float moves freely
• Inspecting for food debris or buildup
When the Float Switch Needs Replacement
Float switches are generally reliable and can last for many years. However, they can eventually fail due to wear, corrosion, or electrical issues.
Replacement may be required if:
• The switch fails a continuity test
• The dishwasher repeatedly overfills
• The dishwasher will not fill with water
• The float switch becomes physically damaged
When replacement becomes necessary, compatible parts vary by dishwasher model.
For a full overview of symptoms, testing, location, and replacement, see the Complete Guide to Dishwasher Float Switches.
Related Guides
Signs a Dishwasher Float Switch Is Bad
How to Test a Dishwasher Float Switch
Where Is the Float Switch Located in a Dishwasher?