Honda Civic Heater Not Working

Last winter, I faced a rather chilly problem with my Honda Civic: the heater suddenly stopped working. Just when the temperatures dropped, I was left shivering on my morning commutes. Have you ever found yourself in a similar situation, bundled up in your car, wondering why the heater isn’t doing its job?

A common reason for the heater in a Honda Civic not working is a low coolant level. The heater core needs sufficient coolant to warm the air inside the cabin. To fix this, check and refill the coolant to the appropriate level. This simple step can often restore the heater’s functionality.

Another reason for a heater malfunction in a Honda Civic could be a clogged heater core. Over time, sediment and debris can accumulate in the heater core, preventing the proper flow of hot coolant. The solution involves flushing the heater core to remove any blockage. This process clears the pathways, allowing hot coolant to flow through and efficiently warm the air.

Finally, a faulty thermostat could also lead to heating issues in a Honda Civic. The thermostat regulates the flow of coolant to the engine and heater core. If it’s stuck in the open position, the engine may not reach its optimal operating temperature, affecting the heater’s performance. Replacing the thermostat with a new one is the solution, ensuring proper regulation of coolant flow and restoring the heater’s efficiency.

Let’s take a closer look at some of the bigger issues you might be facing.

Honda Civic Heater Not Blowing Hot Air

If you’re driving down the road and suddenly your heater isn’t blowing hot air, you might be wondering what the issue could be. There are a few things that cause your heater to stop blowing hot air.

Not Enough Coolant

There are two reasons that your car uses coolant. The first is the more obvious reason, and that’s to cool down your car in the summer months. The second reason for the coolant in your car is for the heater.

The way your car’s system is set up is that it uses the engine to heat the coolant. As you know, your engine gets hot as it runs, and the coolant will run over the engine into the heater core. It may take a few minutes for your engine to heat the coolant enough to blow hot air through your vents.

If it’s taking longer than usual for the air to warm up, it’s possible that you don’t have enough coolant to make it into the heater core. The first thing you can try is refilling your vehicle’s coolant supply. You should have a mixture of 50% antifreeze and 50% water unless you purchase a pre-made solution.

Broken Heater Core

Your heater core is part of your vehicle’s cooling system. It works similarly to a radiator. In your car, it’s made out of aluminum or brass and has little fans that help move the heat around. You can typically find the heater core right behind your dashboard.

The heater core works the defrosters in addition to the cabin heat. If you’re not getting hot air through the car, there’s a chance it’s the heating core. You’ll want to check your coolant levels first to make sure the problem doesn’t lie with the coolant.

If everything appears fine with the coolant, you may need to replace the heater core or have it repaired. If you see signs of your engine overheating, a sweet odor, or fog in the car, then there is a good chance there’s a problem with the core. If you notice your vehicle running through coolant more quickly than usual, that’s also a sign there could be a deeper issue.

Thermostat Is Broken

Another reason that you aren’t getting that hot air from your heater could have something to do with the thermostat. Your thermostat is the gauge that tells your car’s computer whether it needs to signal the coolant and heater to work.

An easy way to figure out if this is an issue for your thermostat is to look at your dashboard’s temperature gauge. If you’ve had the car running for a while and it’s still not blowing hot air, take a look at the needle. If it’s showing that it’s still on C, then you could have a broken or dysfunctional thermostat.

Now, this thermostat doesn’t tell your vehicle that the temperature outside is cold. It’s telling your vehicle’s computer that your engine is still cold, which means it won’t bring the coolant over the engine.

Thankfully, changing out the thermostat is relatively simple. You can probably do it yourself unless you prefer a mechanic to order and replace it for you. If you want to change it yourself, check out the video below for a short tutorial:

Heater Fan Honda Civic Not Working

Sometimes you’ll run into a situation where you can tell the heat is going, but it isn’t being pushed out of the vents. You can hear it, but you can’t feel anything. If that’s the case, there are two things you could check to diagnose the problem.

The first thing you might want to check is the belt itself. If it’s damaged or worn out, it could be causing the fan to operate poorly or not at all. Replacing it could fix the problem.

The second thing to try would be if replacing the belt doesn’t fix the issue. You can check the fuses for your car if that’s the case. If you find any fuses that are blown or damaged, replace them.

If it turns out that neither of those options fixes the problem, you can take your vehicle to a local Honda dealer. There is a chance that the heater resistor is faulty or broken. This can cause the fan to stop working completely.

Honda Civic Heater Not Working at Idle

If your car’s idling and the heat suddenly drops low dramatically, there could be a problem. Your temperature at idle should remain the same as when moving. The first thing you’ll want to do is check the coolant levels. As with the other issues above, the coolant could be your biggest indicator for the problem.

If your coolant is fine, you could use two avenues of approach to find the problem and fix it. You’ll want to check the thermostat first. If the thermostat is faulty or broken, that could be the issue. As mentioned above, the thermostat monitors the temperature of your engine. If it isn’t giving your vehicle’s computer an accurate reading, your heater won’t work.

If the thermostat is operating normally, and your Honda Civic is an older model, there’s a good chance the water pump is bad. With the car idling, check the hoses to the water pump. There should be two of them. One of those two hoses should be much colder than the other hose. If they are both hot or one isn’t as cold as it should be, that could indicate that your water pump is broken.

If neither of those fix the problem, you may want to take your vehicle to your local Honda dealer. They’ll be able to assist you with finding the problem.

Honda Civic Heater Problems

When you’re having an issue with your heater, there are a few things you can do to troubleshoot the problem. It’s suggested that you have a checklist of things to check if a problem does come up with your heater. Everything listed above will help you diagnose a problem, but the list below should be your top priority.

Check your belts first. Make sure they are working properly.
Look at all of the hoses for your heating system. Make sure you’re not broken or cracked.
Inspect your thermostat.
Check the condenser and heater core for debris.

Honda Civic Heater Control Valve

If you’ve looked at everything you can think of and you still can’t find the source of the problem, it could be the heater control valve. Now, it’s important to understand that not all cars will have one of these. Make sure yours does before attempting to remove or replace any parts on your vehicle.

If your car does have one of these valves, there are a few ways you can tell if it isn’t working in your car. Check out the list below.

Heat runs constantly.
You have no control over the heat at all.
There’s no heat.
You have low coolant levels, or coolant is leaking.
The thermostat is reading abnormally high.

If you’re having one or more of the issues listed above, there’s a very good chance that the heater control valve is broken and needs to be replaced. You can take your vehicle to your local Honda dealer to have them do this. Or you can follow the tutorial below to learn how to replace your heater control valve:

Honda Civic Heater Fan Removal

If you know that the heater fan is the problem, you may be inclined to replace the part yourself. This can feel overwhelming if you’re a novice when it comes to cars. However, the video below walks you through how to replace your heater fan with ease: