Car Heater Not Working? Use These Steps to Fix It

By CarsFellow 9 Min Read

The car’s heating system consists mainly of motor-powered fans to blow hot air from the engine bay to the interior of the car. The system is very simple and rarely goes wrong. The only fault that is likely to occur is that the fan stops working due to a break in the electrical circuit.

This circuit consists of a feed wire from the fuse box to the on/off switch on the dashboard or center console and a second wire from the switch to the hatch motor.

The motor usually reaches the body through a separate wire. In most cars, the heater is located below the center of the motor dash, which makes it inaccessible. However, in some cases, the motor is below the bonnet behind the bulkhead.

Your car’s heating system is closely linked to the operation of its cooling system, so one problem in one part can quickly spread to another problem with another. Understanding how heaters work is important for understanding what causes them to fail.

How Does The Car’s Heating System Work?

Your heater is not that complicated. No matter the car, there are some basic parts that every heating system needs to work. The cabin has a heater cover, fan, and control system to allow the driver to change the settings. Your car’s engine generates heat as it runs. Most of this heat escapes through the exhaust pipe, but part of the heat is transferred to the coolant.

As the engine reaches the proper operating temperature, the thermostat allows the coolant to circulate through the engine. So that it “accumulate” more heat and transfer it to the radiator to reduce the temperature level. The coolant heater also circulates in the cover, which can distribute hot air to the cabin.

Important Signs And Causes Of A Broken Car Heater

  • You can smell your car. The radiator fluid can smell sweet, and when it leaks, the car’s cabin can stink.
  • Your windows are foggy for no reason. When a hot condensate gets into the interior of a car, it can cover the windows with feverish and hot burns.
  • The wind is coming out of vents. If the car’s engine is hot and the heat is on, hot air should circulate. If this is not the case, or if the wind that blows is cold, you are in trouble.
  • You need to refill the coolant. If you find that the coolant level needs more attention than ever before, you may be leaking coolant.

Why Did The Heater Stop Working?

The most common cause of heater cover and heating failure is, in general, dirty coolant. Over time, the coolant liquid can become contaminated with particles and dirt from its journey through the engine and cooling system. This can block the heater cover and cause failure.

  • Heater Core

In some cases, dirt and debris can build up and block your car’s heater. Stored contaminants can enter the system with the coolant, and the radiator, engine, or other mechanical parts get rusted or damaged.

  • Antifreeze or Coolant

If the antifreeze surface is too far away, the liquid cannot reach the heater cover. This can happen for a variety of reasons, from leaks to improper filling levels. If the cooler heater cannot reach the cover, no hot air will be generated to heat the cabin.

  • Heater Fan

The heater fan is responsible for dispersing the air in the cabin. Even if every other part of your car’s heating system works properly, you won’t feel hot if the fan doesn’t work.

  • Climate Control

Buttons and knobs that control your car’s heating and cooling system can cause problems if they break down in any way. Climate control depends on the control and communication between the operational parts of the system, so if this process goes away, it can cause the heater to stop working.

  • Wiring and Fuses

Almost every part of your car’s electrical system depends on a series of fuses and wiring. If a fuse is blowing, or if any of the wires are damaged, the heater will not work properly.

How To Repair A Broken Heater

Depending on the problem, it can be as simple as coolant refilling or as complex as a complete heater cover replacement.

Safety Notice

Working on your car, even on small things, can be dangerous. To prevent damage to you or your vehicle, always take appropriate safety precautions. Always wear gloves and protective eye equipment, and always use jack stands when working under an elevator.

It is possible to complete a complete overhaul of your car’s heating system at home, but it is important to remember that replacing the heating cover involves repairs and is a matter of time. You need to make sure you have the right tools and a solid place to work before you start diving into the heater at home.

Low Antifreeze

If your coolant/antifreeze level is low, it’s easy to check and replenish.

  • Let the car cool down. Remove the cap and place a funnel in the opening of the overflow reservoir or the opening of the radiator.
  • Add new coolant until the tank or radiator is full.
  • Reinstall the cap.
  • Start the car and turn on the heat. If the engine stays at room temperature, the air gets hot. Coolant was a problem.

Poor thermostat

If your car’s thermostat is responsible for heating problems, you can take some simple steps yourself.

  • Make sure the car is off and cool.
  • Find a thermostat. It is usually located near the base of the radiator through the main hose.
  • Jack the front of the vehicle and make sure it is securely near the jack stands.
  • Remove the radiator cap.
  • Drain the radiator and coolant by removing the hose and letting the thermostat drip into a bucket.
  • Remove the old thermostat and install a new one.
  • Reconnect the radiator hose.
  • Refill the radiator with coolant.
  • Squeeze the radiator hose to push the water bubbles forward.
  • Reinstall the radiator cap.
  • Get the car down and start the engine.
  • Let the car warm up and check the heater.

Car Bible Dictionary for Heating, Ventilation, and Air Conditioning Terms

  • HVAC

The term refers to heating, ventilation, and air conditioning. In a car, it means a climate control system. Although they are referred to as a group, heating and air conditioning are usually two separate systems in a car that do not work together.

  • Radiator

Radiators are parts of vehicles that drink hot and cold liquids and use a lot of pins and grates to dissipate heat in the air. The coolant then circulates back to the engine, where the radiator accumulates more heat to cool.

  • Fan

Fans are used in automotive climate control systems to move air from one place to another. In this case, the fans are used to push hot or cold air from the climate system into the car’s cabin.


At this point, I hope you know how to fix a car without a heater. This is a very simple task, but it can be very painful because you have so many components to check.

Coolant can be the most basic problem, but in the worst cases, some parts are not working properly, and because of this, they may need extensive repair or replacement if they cannot be saved further.

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