Is your car heater not working? Are you feeling a chill inside your car on even the warmest days? Don’t worry; you’re not alone. 

In this blog post, we’ll explore the reasons why your car heater might not be working and what you can do to fix it.

Common Causes of Car Heaters Not Working

Common causes of a car heater not working include a low coolant level, a faulty thermostat, problems with the heater core, clogged or broken heating controls, dysfunctional thermostats, water leaks, a faulty blower motor, a jammed or faulty blend door, a jammed or faulty heater valve, and a faulty switch or linkage. 

Low antifreeze/coolant levels can also lead to insufficient heat in the coolant causing the car’s heater to not work. 

Regardless of the cause of the issue, it’s important to diagnose and fix the problem before it causes further damage to your car.

Faulty or Broken Thermostat

Stuck open or closed, the part can not only cause issues with the system’s temperature but also prevent it from reaching its optimal level. 

Another reason your car heater may be blowing cold air is if the thermostat is stuck open, causing the car to overcool and not produce enough heat in the coolant to provide warm airflow.

Dysfunctional thermostats occur when the thermostat valve fails to open and close as it should, causing a disruption in the coolant flow and preventing the engine from heating up.

Insufficient Coolant in the Engine

Insufficient coolant in the engine is one of the most common causes of a car heater not working. If your coolant level is too low, there won’t be enough hot liquid in the heater core, resulting in cold air. 

To prevent this from happening, it’s important to check your engine’s coolant levels regularly and top them up if needed.

Problems with the Heater Core

The heater core is a crucial component of your car’s heating system. If it’s not working, you may experience a lack of hot air coming from the vents. Low coolant levels and clogged or broken heating controls can also cause your heater core to malfunction, resulting in cold air coming from the vents. 

To fix the issue, you should check your coolant levels and inspect the heater core for any blockages. You may need to replace or repair the heater core if it is faulty. 

Additionally, you should ensure that all of the other components involved in the heating system are working correctly, such as the thermostats, blower motor, blend door, and heater valve.

reasons why a car heater is not working

Clogged or Broken Heating Controls

Clogged or broken heating controls are a common cause of car heater failure. When you turn the knob and no heat comes out, it may be because the knob itself is broken or the heater control valve may be jammed or clogged. 

It’s important to check the condition of your heating controls and make sure they are functioning properly. If they are not, it’s best to have them replaced as soon as possible to ensure your car’s heater is working correctly.

Water Leaks

There are many different places where leaks can surface, so it is important to check your hoses, radiator, and water pump for any signs of a leak. A coolant leak can prevent coolant from reaching your heater core and could damage your engine, at worst. 

Be sure to top up the coolant and see if it helps. If the level is low due to a leak, it is best to track down the source and get it repaired.

Faulty Blower Motor

A faulty blower motor can also cause your car heater to stop working. This can lead to weak air blowing through the vents, warm air that never gets hot, and a system that fails to start. If the blower doesn’t receive power, check that the blower fuse isn’t blown, as this often indicates an underlying problem. 

If a broken or weak-functioning blower motor is suspected, it should be checked and replaced as soon as possible to avoid any further issues.

Jammed/Faulty Blend Door

A jammed or faulty blend door is a common cause of a car heater that does not work. This happens when the actuator doesn’t move the blend door properly or has failed entirely, preventing the temperature of the air coming from the vents from adjusting correctly. 

To reset the blend door actuator, you must remove it and turn on the maximum heat on the climate control, then turn the blend door until it is fully open. 

If the airflow coming from your vents isn’t consistent, this could be a sign of a faulty blend door actuator.

Jammed/Faulty Heater Valve

A jammed or faulty heater valve is also one of the possible causes of the car heater not working. It is important to check the heater valve if the knob is stuck and no heat comes out when it is turned on. 

The valves in the heater core open to let warm air into the vehicle, but if the valves are closed, the warm air will not come out. The heater valve may be jammed or faulty, and it needs to be checked to make sure it is working properly. 

If it is found to be malfunctioning, replacing it may be necessary in order to get your car’s heating system back in working order.

Faulty Switch or Linkage

A faulty switch or linkage is another possible cause of the car heater not working. If the switch or linkage isn’t working right, it could stop the heater from working right and from blowing air. 

In order to determine if this is the culprit, it is important to check the function of the switch or linkage. If the switch or linkage is jammed, it may need to be replaced in order to get your car’s heater working again.

Next: Why does my car won’t turn over?

Chris Miller

Chris Miller is an auto journalist who specializes in reviewing new cars and providing helpful advice on family vehicles. He has a passion for cars and enjoys sharing his knowledge and expertise with others.

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