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In the 21st century, a high-speed internet connection is no longer just a “nice-to-have”, it’s a necessity. So, it can be frustrating when your Spectrum modem is blinking white and blue. But, some straightforward steps can restore your connection in the blink of an eye.

More often than not, a blinking white and blue light on your Spectrum modem can be normal. However, if the blinking lasts more than a few minutes, it could indicate an issue that needs resolving before you can get online. 

Sometimes the connectivity issue is caused by problems at the Internet Service Provider’s (ISP) end and you’ll have to wait it out. At other times, the blinking may result from a hardware or software issue with your modem.

Follow our handy step-by-step guide to help you resolve the issue or eliminate the potential causes, ready for a call with a Spectrum technical engineer.

Is a White and Blue Blinking Lights on a Modem Normal?

Spectrum modems use a light system to tell the user about the modem’s various functions. By observing the color or the lights’ statuses, you can quickly get an idea of whether the modem is switched on, connected to the internet, or experiencing an issue.

Typically, a solid blue light indicates that your Spectrum modem is connected to the internet and transmitting in high-speed or DOCSIS 3.1 mode. By contrast, a steady white light means that your modem is connected to the internet, but only at a standard speed or using DOCSIS 3.0 bonding.

When you power up your Spectrum modem, the lights will blink blue and white. It’s a normal part of the boot-up process and shows that your modem is trying to establish a connection with the Internet Service Provider (ISP). It should typically take 2-5 minutes for your modem to connect and enable you to access the information on the internet.

When Does the White and Blue Blinking Light Indicate an Issue?

If your Spectrum modem’s lights have been alternating between blue and white for more than five minutes, you’re likely experiencing a connectivity issue. A connectivity issue could be caused by:

  • A service outage in your local area;
  • An incompatible modem;
  • A hardware failure within your network setup; or
  • A software issue with your modem.

Let’s look at some of the easy steps you can take to troubleshoot your modem’s blue and white blinking lights.

How to Fix Your Spectrum Modem’s Blinking Lights

With almost 30mil customers, Charter Communications’ Spectrum is the second largest provider of internet and cable services in the USA. Many of its users expect high-speed connectivity and outstanding customer service. But once in a while, you may not get the instant connection you expect.

So what can you do to fix the white and blue blinking light on your Spectrum modem?

1. Check for Outages in Your Area

Before you spend a lot of time tracking down a hardware or software issue with your modem set-up, check whether there’s a reported service outage in your area.

The easiest way to stay up-to-date with service outages in your area is to set up outage notifications in your MySpectrum app:

  1. Open the MySpectrum app and log into your account;
  2. Navigate to Account > Set Notifications > Manage Push Notifications;
  3. Turn on push notifications for “Outages”.

Alternatively, you can check the Spectrum website for the latest outages.

If your area is experiencing service outages, then sadly, there’s nothing to do except wait until service is restored.

2. Check You’re Using an Authorized Spectrum Modem

You’ll need to use an authorized Spectrum modem to access the Spectrum network. Spectrum will often have provided you with a compatible modem when you registered with the service. Currently, Spectrum has authorized the following modem models:

Manufacturer Authorized Model
  • ONU (SONU) Modem
  • TC4400
  • DPC3000
  • DPC3008
  • DPC3010
  • U10C035
  • DDW36C
  • SB6120
  • SB6121
  • SB6141
  • Surfboard 5100/5101/5101N

If you’re not using one of these authorized models, then it’s worth trying one to see if it resolves your connectivity issues.

3. Reboot Your Modem

Simply rebooting your modem can be enough to resolve its connectivity issues. The safest way to restart your modem is to hold down the integrated power button, usually found at the back of your device. Hold the button to power down, wait around 15 seconds, and press the button again to power up.

If you don’t have a power button or it’s not responding, you can also turn the power off at your wall outlet or power strip. Just make sure you’ve saved any work if you’ve got other devices plugged in!

The whole reboot process should take a few minutes. After rebooting, if you’ve still got a blinking blue and white light, it’s time to move on to the next step.

AdobeStock_420553265 Male electrician connecting coax cable antenna wire to wall outlet

4. Check Your Cables ; Connection Points

If a reboot didn’t do the trick, the next thing to do is systematically check all of your cable and connection points to see if anything has come loose or has become damaged over time.

Coaxial Cable 

Your Spectrum modem connects to the ISP via a coaxial cable, which should be connected to the back of the device. Check that:

  • The cable is plugged in;
  • The connection is solid and the joint is not bent or loose; and
  • Your cable is not damaged.


If you’ve got an internet and TV bundle from Spectrum, you may use a splitter to connect multiple devices to your broadband . Splitters are subject to wear and tear and may be damaged by moisture.

To check if the splitter is the problem, remove it from the equation. Plug your modem directly between your coaxial wall outlet and your computer. If you’ve managed to restore the connection, then great! You’ve found the issue and can buy a replacement splitter at a later date.

Coaxial Outlet

The problem could be your home’s coaxial outlet. If you’re fortunate enough to have more than one coaxial outlet in your home, you’ll be able to check this for yourself. Simply take your modem to an alternative coaxial outlet, set it up according to the manufacturer’s instructions and wait to see if the blinking stops.

If you don’t have an alternative wall outlet, you might need to call an engineer to repair your existing outlet or install a new one.

Other Network Devices

Some network setups use a separate modem and router to connect to the internet, while others might use a cable or a junction box. You can repeat the checks above for each device to check whether these connection points are the source of your blue and white blinking light.

5. Check Your Modem’s Physical Environment

Most people know that computers can overheat and take great care of their computer’s location within their home, ensuring nothing obstructs it and often positioning a fan nearby.

Like your computer, your modem can overheat if it’s located close to another device like your TV or in a spot with limited air circulation.

Check that there’s nothing that could interfere with heating regulation around your modem and position it a few feet above the ground. 

6. Check Your Modem’s Firmware

If you’ve followed all the steps above and still have not resolved the blue and white blinking light on your Spectrum modem, it’s worth checking your modem’s firmware version to ensure it’s up-to-date. Older versions of firmware may no longer be supported, which can cause connectivity issues.

Compare your modem’s firmware version against the most recent version on the manufacturer’s website. If you find a newer version, you’ll need to borrow an internet connection to download and install the patch to your modem manually. 

The overall process should take around 20 minutes. Don’t forget to reboot your modem after the installation!

7. Call Spectrum Customer Care

If you’ve exhausted our handy step-by-step guide and still haven’t successfully stopped the blue and white lights from blinking, then you’ll need to contact Spectrum’s Customer Care team.

They may advise you of an unreported service outage and an estimated time of repair. Failing that, they should organize a call-out from a Spectrum engineer. Also, here’s a helpful youtube video we found below if videos are your thing.

The Bottom Line

Nothing is more frustrating than sitting at your computer to “quickly” type out an e-mail or catch up with an urgent piece of work, only to be met with flashing blue and white lights on your Spectrum modem.

Sometimes the connectivity issues are caused by problems at Spectrum’s end , such as service outages or engineering work in your local area. But when the issue appears to be isolated to your connection, these handy steps can help you quickly identify the root cause of the problem.

Knowing what’s causing the blue and white blinking light is half the battle. Once you’ve determined whether the issue is with your modem, cables, or other devices, you can often find an inexpensive solution such as buying a new cable or splitter.

Failing that, you’ll be armed with enough information to help Spectrum Customer Care resolve your issue more efficiently.