Brightness Button Not Working? 4 Easy Fixes

Last Updated : 05 Dec, 2025

If your laptop or desktop brightness buttons suddenly stop working, it can be frustrating especially when the screen becomes too dim or too bright. This issue usually happens due to faulty drivers, disabled function keys, dirt in the keyboard, or minor software glitches. In this guide, we’ll walk you through four simple and effective fixes to restore your brightness controls in just a few minutes.

A quick restart often resolves minor brightness key issues.
Dirt or dust under the keys can block brightness controls.
The Fn (Function) key may be required to adjust brightness.
Windows troubleshooting tools can automatically detect and fix hardware issues.
Updating keyboard drivers can resolve conflicts and restore key functionality.

4 Ways to Fix Brightness Button Not Working

Many users face issues with the brightness button which sometimes does not work properly in the system. That's why here we'll mention 4 easy ways to resolve this problem.

Method 1: Restart Your Computer

Before trying anything advanced, restart your laptop or PC. A reboot clears temporary software glitches and resets keyboard functionality.

Steps:

Shut down your system completely.
Turn it back on after a few seconds.
Try pressing the brightness buttons again.

Best for: Temporary system glitches, frozen keyboard functions.

Method 2: Clean Your Keyboard

Brightness buttons often stop working when dust, crumbs, or debris get stuck under the keys.

Steps:

Turn off your laptop.
Flip it gently or keep it at an angle.
Use compressed air to blow dust out of the brightness keys.
Alternatively, use a soft toothbrush to clean around the keys.
Let any moisture fully dry before turning the system back on.

Best for: Keys physically stuck or not registering presses.

Method 3: Make Sure the (Fn) Function Key is Enabled

Many laptops require pressing the Fn key + brightness key to change brightness.

Try this:

Hold Fn and press the brightness up/down keys.
On Windows laptops, Fn is usually near the Ctrl or Windows key.
On Mac, the Function key is next to the Command key.

Tip:
Your keyboard may have Fn Lock enabled, which can change how brightness keys behave. Disable Fn Lock if brightness keys don’t respond.

Method 4: Run Windows Hardware & Devices Troubleshooter

Windows 10/11 includes a hidden troubleshooter that detects and repairs hardware issues like keyboard malfunction.

Press Windows + R to open Run.
Type the following command and press Enter:

Command: msdt.exe -id DeviceDiagnostic

Output :

This will launch the Device Diagnostic tool to specifically check for issues with connected devices like your keyboard. Click on Next to Start the Diagnostic.