Nest Fan Not Turning On with AC?

Do you know why your Nest fan not turning on with AC? We have the answers and solutions you’re looking for!

You’ll notice this issue right away when an unbearably hot day rolls around, and your Nest Thermostat does not turn on your fan.

If you’re experiencing this issue, the culprit is most likely related to your device’s power and sensors.

It could also be a software issue that disrupts the power delivery to your Nest.

If your Nest fan does not turn on with your AC, the first thing you need to check is loose wiring. You want to make sure that the wires in your thermostat are connected to the right terminals. Replacing the batteries also helps since they provide supplemental power.

Let’s take a look at the different causes of this issue before we move on to solving it.

Why Does Nest Fan Not Turning On with AC

There are several reasons that cause your Nest fan to not turn on with your AC.

The most likely cause is a power delivery issue that disrupts the operation of your Nest Thermostat.

Using different settings can also cause this as it will not power up your fan at a certain temperature window.

Here are the problems that can affect your Nest thermostat’s fan powering on with your AC:

1. Loose Wiring

Your Nest is wired into your home’s power directly. If some of these wires come loose, it can affect certain features of your thermostat.

2. Old Batteries

Even though your Nest is hardwired into your home’s power, it still uses batteries to ensure optimum voltage levels.

If the batteries are old, the voltage can drop and affect the operation of your thermostat.

3. Wrong Settings

Your nest can control your entire AC system. Using the incorrect settings can affect the systems that it links to.

4. Software Issue

Outdated software, glitches, and bugs can cause this particular problem. It’s mostly temporary, but it can still affect how your thermostat controls your system.

These are the issues that can impact your Nest thermostat’s control of your fan.

Now, we can go ahead and look at the possible solutions so you can get rid of this problem as quickly as possible.

How to Fix Nest Thermostat Not Turning On Fan with AC

There are quite a few troubleshooting steps to go through, but before you start, there’s one step that we would like you to try.

Make sure to restart your Nest thermostat by pressing on the ring and holding it for 10 seconds.

The screen will switch off, and you can turn it on again. We just want you to start with one of the most common steps that can save you a ton of time if it works.

In case it doesn’t resolve the issue, here are the next steps you should take:

Solution #1: Cycle Your Nest Thermostat’s Breakers

If a simple restart does not fix the issue. You want to do a more advanced approach.

Since your Nest is not plugged in and wired directly to your home’s power, the only way to cut it off is to turn off your breaker.

Doing this will ensure that power is drained from the thermostat and that any bugs and glitches are cleared from the system.

Here’s how to cycle your Nest thermostat’s breakers:

Turn off your Nest by pressing the thermostat ring.
Hold it for 10 seconds.
Turn off the breaker your Nest is connected to.
Wait for at least 2 minutes.
Press the ring to turn it on again.

Note: Some of your other outlets will not work depending on how your Nest is connected with your circuit breakers.

Solution #2: Replace Your Nest Thermostat’s Batteries

Your Nest comes with batteries that serve as a backup or supplemental power. There are times when your home’s electricity source experience fluctuations.

The batteries are the ones that ensure that the voltages and currents are maintained, so your thermostat performs optimally.

If the current batteries of your Nest are drained, it will not be able to keep up with maintaining the power levels that are delivered to your device.

This is when you will experience your AC system acting up and malfunctioning. If this is your case, it’s time to replace the batteries.

Here’s how to replace your Nest’s batteries:

Pull the thermostat from the base.
Remove the batteries found at the back of the display.
Replace with two new AA batteries.
Place your thermostat back into the base.

Pro Tip: Some Nest models like the Thermostat E or Learning Thermostat do not come with AA batteries.

You will have to charge their built-in ones using a USB cable.

Solution #3: Reconnect Your Thermostat’s Wires

If your Nest thermostat does not turn on the fan automatically with your AC when it’s supposed to, it’s a power issue. One of the causes of this problem is loose wires.

It can also happen if the cables are not connected properly. You will have to reconnect them to the thermostat’s terminals, so they start working again.

Here’s how to reconnect your thermostat’s wires:

Turn off the power to your Nest by switching off your circuit breakers.
Pull your thermostat off the base.
Pull out one of the wires to check it.
Insert the wire back into the connector.
Repeat with the rest of the wires.

Tip: You will know that the wire is inserted properly into the connector since the buttons will stay down.

Solution #4: Check the Fan Settings on Your Thermostat

Sometimes the issue can be as simple as the fan setting being switched to the off position.

There are a few ways to control the fan with your AC on your Nest thermostat.

You can manually turn it on or off or even set a schedule. It can happen that some of these settings have changed where the fans are disabled.

Here’s how to check the fan settings on your Nest thermostat:

Tap on the thermostat’s touch bar and choose Fan.
Pick a duration on how long you want the fan to run.
Select Start to start the fan.
The fan will switch off automatically when the time is up.

Note: You can also set a fan schedule by going to your thermostat’s Settings > Fan > Schedule.

Set the duration you want your fan to run each day and configure it always to run.

Solution #5: Reset Your Nest Thermostat

If none of these troubleshooting steps work, there’s still one you can try that will solve your problem.

Resetting your thermostat can feel like a last resort type of solution, but it does fix several issues, including this particular one.

It’s one of the best fixes that clears up everything on your thermostat, giving it a chance to start up fresh. This means that you will be able to configure it so that it will not have any contradictions.

Here’s how to reset your Nest thermostat:

Go to your thermostat’s settings.
Choose the Restart option.
Select Factory reset.
Confirm your choice to start the process.

Tip: Choosing the Factory reset option will clear up all your settings, including preferences. Be prepared to set up your thermostat again.

These troubleshooting steps should resolve your issues in no time. However, if none of these do the trick, you face a much deeper problem.

Contact Nest’s customer support so they can guide you with the next steps to take.

Bottom Line

You now have a pretty good idea of what causes your Nest fan not turning on with AC and how to fix it.

As long as it’s not a serious hardware flaw, you should be able to resolve it just by following the steps we described. You don’t even need any technical expertise to fix it.

However, if you’re not successful, Nest’s customer support can offer more technical help if the need arises.

Kevin Wood

Kevin has over five years of experience working in various Tech startups and providing Technical solutions. He has contributed to many Tech publications and websites.