Hey, Why is My Car's Heater Not Working?

Hey, Why is My Car's Heater Not Working?

Your vehicle's cooling system is responsible for the heat that is generated inside the vehicle. The cooling system has several components that maintain proper engine temperature to provide for proper combustion and low emissions from the exhaust pipe. The secondary by-product of this cooling system is to transfer the heat from the coolant to the inside of the vehicle through a heater core. Once the coolant is transferred through the heater core, climate control blends air to maintain the proper temperature inside the vehicle.

Is The Heater in Your Car Not Working?

The heater isn't working because of issues with the blower motor. This can be caused by internal damage or wiring problems preventing power from getting to the blower motor. However, in less common cases, the issue might be related to something different, like a restricted heater core, faulty blend door actuator, faulty coolant control valve, or a stuck-open thermostat.

A car heater not working can involve several different car systems! Ignoring heating problems can jeopardize your comfort, create further issues, and drain your wallet.

Consider consulting a skilled expert who can pinpoint and recommend future actions to prevent and fix the problem. This keeps your vehicle running smoothly, allowing you to enjoy a cozy ride worry-free. Remember, if left unattended, a minor glitch can snowball into a major headache.

Let's Get To The Bottom Of It!

  • Q: Is the blower motor unresponsive or working intermittently?

    The blower motor in your car's heater is like a fan that pushes air across. Over time, this motor can wear out and draw more electrical current. When this happens, the wires and connectors can get hot and melt, leading to a weak and intermittent connection. As a result, the blower motor may work sometimes but not always. More rarely, this can trigger the "check engine" light on the dashboard.

  • Q: Is the heater blowing cold air even after warming up the engine?

    Certain vehicles have a valve called the "heater hose control valve." Its job is to restrict the amount of hot coolant that goes into the heater core, which helps improve the effectiveness of the air conditioning system. This valve can operate in different ways: mechanically, by vacuum, or electronically. If this control valve malfunctions, it restricts the hot coolant flow to the heater core. As a result, even after the engine warms up, you won't get any hot air from the heater vents. In rare cases, this might accompany a coolant leak, weak airflow from the vents, and clicking noise under the dashboard.

  • Q: Is the temperature coming from the heater always the same regardless of your adjustments?

    Inside your car's heating and air conditioning system, there's the "airbox." It has plastic doors that control the airflow to manage the temperature. These doors are moved by small motors called "door actuators." If these doors break, the actuator can't control them anymore and gets stuck in one position. Since the doors blend hot and cold air, the temperature won't change, no matter what you set on the control panel. This rarely accompanies a "check engine" light on the dashboard.

  • Q: Is the "check engine" light active on the dashboard?

    The thermostat in your car helps the engine warm up in a calculated time to reduce emissions. But it can get stuck open and break down after wear and tear. When the thermostat sticks open, the engine takes longer to reach its ideal temperature. This warm-up delay is alarming to the engine computer, activating the "check engine" light on the dashboard.

All related issues checked?

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Hey, Why is My Car's Heater Not Working?

Vehicle Health Inspection Proof

Explore the following typical inspection results that show a potential cause for the symptom and select the one you believe is similar to your vehicle's issue.

Restricted Heater Core

This proof image confirms the restricted flow in the heater core, which is causing the heating problem in the vehicle.

When the customer brought in their vehicle, they mentioned that the heater only worked while driving at freeway speeds. The heater's temperature wouldn't act right if they drove at normal speeds.

The technician confirmed the heater was blowing ambient air during the test drive. So, it wasn't working as expected.

To diagnose the issue further, the technician conducted a vehicle health inspection. During this inspection, they didn't find any immediate problems related to the customer's concern.

However, to investigate the heating problem, the customer authorized additional diagnostics. Then, the technician used an infrared digital thermometer to read the temperature of specific car parts. They started the engine and measured the temperature at the upper radiator hose, which was 198ºF. 

Then, they checked the temperature of the heater hose going into the heater, which was 199ºF. However, the temperature coming out of the heater core was only 85°F. This temperature difference means the heater core was restricted, reducing coolant flow.

Based on the findings, the technician suggests trying a process called back-flushing the heater core to see if it helps restore proper coolant flow. They recommend replacing the clogged heater core if this attempt doesn't work.

Does the issue look like this? if not accessible your shop will document it

Typical Fixes to Address the Cause(s)

The following chapters bases themselves on experiences from our auto repair shop; we'll describe related problems' causes and fixes.

"Heater core replacement" fixes "Restricted heater core"

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Sometimes a problem is more challenging to describe than it initially looked like. If you are not sure your problem is described by this article, please find below similar vehicle symptoms, which might describe better the issue you are experiencing.

Other things your auto repair shop might talk about:

Heater control valve. Cooling system. Cabin air filter. Coolant level. Radiator cap.

Is Heater Not Working
Your Issue?