How to Quickly Fix Nest “Wiring to Your Equipment Has Changed”


If you see the dreaded “The wiring to your equipment has changed” message on your Nest, you can usually dismiss it by pressing Continue.

But if the notification keeps popping up, we’ll have to do something about it. Wave goodbye to freezing cold mornings.

Here’s how to fix the “The wiring to your equipment has changed” notification on your Nest Thermostat:

  1. Restart or factory reset your Nest Thermostat.
  2. Ensure that your Nest Thermostat uses the C-wire.
  3. Ensure that your HVAC system is working correctly.
  4. Charge or replace the batteries in your Nest Thermostat.
  5. Disconnect the Y wires temporarily.

This article will explain a few reasons why your Nest Thermostat keeps showing the notification mentioned above. I’ll teach you how to fix it so it won’t pop up anymore.

1. Restart or Factory Reset Your Nest Thermostat

A simple restart or full reset could solve your issue if your Nest worked fine until recently.

A random software glitch could cause the message to pop up.

Or maybe a recent automatic update broke the Thermostat’s firmware.

Whatever the cause might be, you should first try a reset. You won’t lose any of your personalized thermostat settings, so don’t worry.

Here’s how to reset your Nest Thermostat:

  1. Press the Nest ring.
  2. Go to Settings.
  3. Select Reset to open the expanded menu.
  4. Select Restart.

Give the Nest a couple of minutes to turn off and come back on.

If the message is gone, hooray!

If not, you might want to try a full reset

Note that a complete reset wipes all your Nest data and requires you to set it up with your Google account again. 

So, it should be your last resort if you suspect it’s a software bug and not a wiring issue.

Here’s how to reset your Nest:

  1. Press the Nest ring.
  2. Open Settings.
  3. Open the Reset menu.
  4. Select All Settings.

If you’re still getting the notification, don’t worry. 

2. Ensure That Your Nest Thermostat Uses the C-Wire

If you installed the Nest Thermostat in summer and it worked normally until the freezing winter season, it’s because your Thermostat uses a Y1 wire for power. Let me explain.

Thermostats typically get power from a common wire or C-wire for short.

The C-wire is a 24V wire that’s connected to your heating system on the other end. 

The Nest Thermostat needs the constant flow of low-voltage electricity that the C-wire provides.

If your HVAC doesn’t have a C-wire, your electrician probably fed the Y or Y1 wire through the C terminal instead.

The Y/Y1 wire is either from your cooling system or your heat pump compressor.

Your AC probably has an automatic shutdown switch when the refrigerant pressure gets too low in cold weather.

If you only get the error message in cold weather, this is why.

Thankfully, the solution is quite simple. Here’s what you can do:

  1. Switch off the main power for your HVAC in your home’s breaker box.
  2. Remove the Nest Thermostat off the wall.
  3. Ensure that your C-wire is in the C terminal. If you notice that the C-wire is unused and another wire is in the C terminal, remove it and plug in the C-wire.

It’s also possible that you don’t have a C-wire in the first place. 

In that case, it’s much better to use the G-wire in the C terminal instead.

The G-wire powers the fan, so you won’t face any weird issues.

However, this requires a few extra steps.

You’ll have to install a jumper wire between the Y and G terminals on your HVAC’s mainboard.

Word of Advice TV has a great video explaining how to do it:

Another solution is to buy the Google Nest Power Connector.

It’s a C-wire replacement designed to work with the Google Nest Thermostat.

3. Ensure That Your HVAC System Is Working Correctly

If your HVAC system has gone through a couple of years without maintenance, perhaps it’s time to call someone to check it.

HVAC systems need to be checked annually.

Your HVAC consists of dozens of components that can fail, such as:

  • Fans
  • Compressor
  • Heat pump
  • Blower motors
  • Air filter
  • Evaporator coils

You’ll see the error notification pop up if a single component breaks.

It’s best to call a professional individual or service to do the maintenance for you.

4. Charge or Replace the Batteries in Your Nest Thermostat

Your Nest Thermostat uses either a non-removable rechargeable battery or a standard AAA 1.5V battery.

If the battery runs out of juice, your Nest Thermostat will malfunction.

The “Wiring to your equipment has changed” message pops up because the Thermostat isn’t getting enough power.

It’s often accompanied by a low battery message.

To charge your Nest Thermostat, remove it from the wall and plug in the appropriate USB cable. 

The Nest Thermostat E, 3rd gen, and 2nd gen Thermostats use Micro-USB.

The 1st gen uses an old-school Mini-USB cable.

Use a phone adapter or computer to charge the Thermostat.

If the Thermostat runs on AAA batteries, pop them out and put in a pair of new ones. 

5. Disconnect the Y Wires Temporarily

Before we talk about this solution, I must warn you: Your AC won’t work until you reconnect the Y wire again.

This is only a temporary workaround so that you don’t freeze to death while waiting for a professional to fix your wiring.

Disconnecting the Y/Y1/Y2 wires from the AC will make the error message go away.

Here’s how to do it:

  1. Switch off the main power for your HVAC system.
  2. Remove the Nest Thermostat from the base.
  3. Remove all wires labeled with a “Y” from their respective terminals.
  4. If you have Rc and Rh wires, disconnect the Rc one.
  5. Insulate all exposed wire ends with electrical tape.

This will get your heating back up and working again.

But you should connect a C-wire or Google Nest Power Connector to the C terminal so that your Thermostat receives the energy it needs.

Final Thoughts

If you see a wiring-related error message on your Nest Thermostat, it’ll often go away with a simple reset or restart.

But if the error is accompanied by a malfunctioning HVAC, you should check your wiring.

Also, you may need to get the HVAC system checked by a professional.

Nelson Barbosa

I'm an engineer in love with smart home tech. On my website, I share useful tips and tricks to help my readers get the most of their devices and make their lives simpler by adding just a drop of technology in everyday routines!

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