Broadband Hardware

What does the red light mean on a Mercusys Halo router?

Mercusys Halo routers
A fine mesh: the Mercusys Halo system

Whether you have the Halo H30G or the more powerful Halo H50G, Mercusys provide great value mesh routers. But what does a red light on a Merusys Halo router mean? And what about the other colours? Let’s find out

Solid red

Your Halo has a problem. According to Mercusys, you should try the following:

  • Reboot the main Halo and see if the internet connection resumes (wait for about 3-5 minutes)
  • Disconnect the Ethernet cable that goes between your modem and your main Mercusys router, and leave it for ten seconds before reconnecting

To add to this advice, it sounds as if the red light indicates a lack of internet connectivity. In this case, I’d also recommend the following checks:

  • Ensure the modem that your main Halo unit it connected to is working as expected – it may be worth giving this a reboot
  • Give your ISP a call to see if there’s a fault with your broadband line

Pulsing red

The Halo is no longer connected to your main Halo router. Check that they’re close enough together and try rebooting each in turn to re-connect them.

No light

There are two reasons why you may not be seeing a light:

  1. There is no power to the Halo – check the power cable to make sure it’s securely plugged in
  2. You’ve switched off the LED light in the Mercusys app. If you go into Advanced > LED Control, you can both turn the LED off entirely or switch it off at night

Solid yellow

The Halo is starting up – give it a few minutes.

Pulsing yellow

This light means that you Halo is being reset. If you need to reset your Halo, you do this by pressing the button on the rear of the device. Press this for one second to reset the Halo to factory default settings.


The Halo is setting itself up. It will be solid blue at first, before pulsing to indicate that it’s ready. You’ll need to complete setup in the Mercusys app.

Solid white

The Halo is connected and all is well. This is the light you want to see most of the time!

Pulsing white

The Halo is updating its firmware – this should just take a little while to complete.

About the author

David Artiss

Works for Automattic Inc., the company behind and Tumblr. Tech geek, international speaker and occasional PC Pro podcaster. Lover of Lego and video games.

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