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TCL TV Dimming on One Side (Causes and How to Fix)

As a proud owner of a TCL TV, I recently experienced an issue where one side of the screen was dimmer than the other. I was frustrated and wanted to get to the bottom of this issue.

After doing some research and testing, I’m here to share what I learned about the causes and how to fix this issue. In this blog post, I’ll explain what causes one side of a TCL TV to dim and how to correct it.

If one side of your TCL TV dims, the cause is usually faulty hardware, such as the backlights, cables, or T-con board. TCL TVs may also dim if their software is out of date, which can cause your device to glitch due to unresolved system bugs.

Faulty backlights, cables, T-con board, and outdated software are common causes of a TCL TV dimming on one side.
Put your TV in a power cycle as the first step to fix the problem.
Check all plugged cables and ensure they are securely plugged in.
Replace any faulty LEDs with new ones if needed.
Update your TCL TV’s software if it is out of date.
Contact your service provider for proper inspection if all else fails.

Common Causes of TCL TV Dimming on One Side

TCL TVs suffer from display problems just like any other TV. Do you know what’s the reason, though?

Faulty Backlights

A faulty backlight is one of the most common reasons for a dimming LCD screen.

Most TVs have a filtered light system at the back of the display that generates the images you see on your screen. When this system gets damaged, the backlights suffer as well.

A simple way to check if your TV has faulty backlights is to turn on your TV and shine a light as close as possible to the screen. If you can see an image, then your blacklights are busted.

Faulty HDMI Cable

A faulty HDMI cable is a reason that’s often overlooked. At a glance, your HDMI cable may seem perfectly fine, but regular wear and tear can damage the insides.

To confirm whether this is the cause, try to connect your HDMI cable to another device. If the same dimming problem occurs, it’s time to replace the cable.

Faulty T-Con Board

A TV’s T-Con board produces the panel signals that make sure you get the right picture at the right time. It’s responsible for the device’s video processing.

If this board is damaged, your TV may display a black, blank, or distorted screen. It can even cause one side of the TV to dim.

Outdated Software

TCL TVs aren’t new to frequent updates. Their Android ecosystem requires them to generate updates to fix common bugs. Typically, these software updates make your device faster and better. 

If your TCL TV is dimming on one side, it’s possible that your software is outdated.

Unexpected Interferences

Unexpected interferences, such as other devices connected to your TV, can also be the cause of one side of your TV dimming.

If another device is connected to your TV, it can cause a faulty signal transfer between the devices.

How to Fix TCL TV Dimming on One Side

You can fix your TCL TV problem with the following solutions. Some are easier than others, but it’s worth trying them all to see which one works for you.

Put Your TV in A Power Cycle

Putting your TCL TV in a power cycle can solve the dimming problem. This solution is the most ideal if you’re only having temporary glitches after a software update.

  1. Turn your TV’s power off and unplug it
  2. Press and hold the power button for at least ten seconds
  3. Wait for about 15 minutes
  4. Plug your TV in
  5. Turn your TV on
  6. Check if there’s still a dimmed area

If the dimming problem persists, there are other ways to fix the problem.

Check Plugged Cables

Checking your plugged cables may be the easy fix you’re looking for. Simply check that all of the connected cables at the back of your TV are securely plugged in.

If any plugs are loose or old, you should replace them with new ones. Even if they still work, faulty plugs and cables can damage the TV’s internal components.

Fix Faulty Backlights

You’ll only need a few tools to fix your faulty backlight:

  • Screwdriver
  • LED flexible strips
  • Wires
  • Soldering iron

Before taking any steps, make sure that your new LED strips have the same values as your old strips, i.e. the same voltage and amperes.

Here’s how to fix faulty backlights:

  1. Open the back of your TV using a screwdriver
  2. Lift the back panel of your TV
  3. Unscrew any metal sheetings
  4. Remove the bezel to access the backlight. The black diffuser should be under this bezel
  5. Inspect all LEDs and find the faulty ones
  6. Replace all faulty LEDs with new ones

Update Your TCL TV

When an update is available, it’s always a good idea to install it on your device. This guarantees that you get the most out of your TV.

You can update your TCL TV with these simple steps:

  1. Click the Home button on your remote and go to the Settings menu
  2. Select more settings
  3. Select Device Preferences, then About
  4. Select System Update
  5. From the pop-up display, select Network Update
  6. Your TV will start to look for available software updates. If one is available, click download
  7. Wait for the download to finish
  8. Once downloaded, click OK to confirm

Call Your Service Provider

Calling your service provider is your last resort. If you’ve tried every possible fix and the problem persists, it may be time to call in a professional.

Simply call your nearest TCL service center and ask for an inspection of your TV.


A TCL TV with dimming on one side isn’t a hopeless case. Sometimes, you can even solve it with a simple power cycle.

However, if worse comes to worst, it’s best to give your service provider a call for proper inspection.

Read more: TCL TV only works in movie mode