Why Is My Car Heater Not Working?

Why Is My Car Heater Not Working?

Car heaters are a miracle in winters. Nothing helps against the cool breeze entering through the windows, chilling your hands on the steering wheel, then a hot air blasting heater.

However, if your car heater has stopped working, it could make driving in chilly weather a nuance.

Before jumping to fix it, you need to look at the reasons causing this distress in the first place.

Car Heater Not Working Causes

These fundamental reasons would help you understand your problem better and how it was caused in the first place.

In this article, we will be looking at some of the main reasons that cause your car heater to stop functioning and the solution that may assist you in making it work again.

Reasons Why Car Heater Might Fail To Work

To answer why your car heater has stopped working, we need to look into the troubleshoot that caused this in the first place; only after then can it be quickly resolved.

Heating systems are composed of a heater core, heater fan, car’s coolant system, and HVAC control system.

All these components integrate to make a thoroughly efficient and functional heater.

If yours is not working, then it’s a high chance one of these components might not be working proficiently.

The following are the most fundamental issues and problems people face regarding why their car heater isn’t working.

These primary and minor issues may cause your heater to go haywire. The essential solutions for quickly retrieving your heater are also described below.

Note that professional mechanics should make some changes.

HVAC Controls

HVAC controls, also known as the Heating, Ventilation, and Air Conditioning features, are one of the main features of a vehicle.

The function of this equipment in the car is to regulate the functioning of the cooling or heating system.

If this system is broken in your car, the heating system won’t regulate the temperature, providing you with cold or no air.

There are three more possible problems that cause irregularity in your car heater.

Faulty Control Module

This troubleshoot is caused within the module, which is the physical unit an individual can use to set the temperature or other settings.

It contains a screen, dials, and buttons. These components can be broken or malfunction, causing disturbance to the whole HVAC system.

Control Module controls the functioning and performance of the vehicle. It ensures that the vehicle operates at an optimum state and isn’t overheating or causing any trouble.

It’s also a digital and analog interface with buttons and a screen to control the car’s functioning.

The fault in the Control Module could easily damage the vehicle and not only the car heater.

A faulty or failing control module’s symptoms can be described as vehicle failing to start, heater not functioning, engine stalling, engine performance issue as well as poor fuel economy or drainage of fuel quickly.

These are the few things that might begin to trouble your heater and, eventually, your vehicle.

After diagnosing the main issue, head towards the problem-solving part. It’s not usually recommended for beginners to do a DIY on your vehicle as professionals only fix these.


The only possible and rational solution for this issue is to replace the whole module with all the components with a new one.

Replacing a vehicle module for a car heater is quite challenging, so a professional mechanic handles this type of work shield.

Failed Sensors

If all components and the whole module works fine itself, then the subsequent fault you might need to look into are failed sensors and know why your heater isn’t working?

Every modern car or HVAC controls system installed has these two primary sensors; a temperature sensor placed on the outside of the car and a temperature sensor placed inside the car.

These two temperature sensors work together to determine the air coming from the vents.

With the sensors not working, the air that enters the vehicle is the same air circulating in the car’s surroundings.

Without the functioning of the sensor, the outside and inside air won’t be correctly determined hence providing the driver with the same polluted air.


To resolve this problem, you need to visit your nearest mechanic for a quick repair as to why your car heater isn’t working. You can easily replace the sensors with new ones.

Why My car Heater Isnt Working

Bad Blend Motors

If all goes well and your car heater isn’t working, then the problem might be a little complicated and different from all.

As the name suggests, these blend motors allow the air to circulate through it and blend the desired amount of heat or coolness that the driver wants.

The driver or user sets a temperature, and these blend motors regulate the air from outside to the desired temperature and vent it into the car.

A broken blend motor will not perform this function effectively. The air you receive is plain and quite stale and suffocating.

The most noticeable problem in a broken blend motor is that it’s pretty noisy, even if it’s not damaging the internal controls.

The failing blend motor will not provide you with pleasant warm air as it will not blend the air.


The HVAC control system is a built-in system. These components are supposed to provide the user with the desired temperature.

For such complex and perplexing issues and problems, you must visit a mechanic to fix your car heater.

Bad Thermostat

The thermostat is another one of the components that helps the car heater work efficiently.

A car’s thermostat plays an efficient role in controlling the flow of hot water through the radiator while adjusting the coolant flow.

A failing thermostat could result in giving off cold air instead of warm air to heat your car.

The signs that show your car’s thermostat is failing are overheating the engine, leakages, temperature fluctuations, a full expansion tank, and others.


To fix the failing thermostat, an individual must know why it was caused in the first place. A choked cabin air filter, a failed thermostat, or failed heater core can be the main reasons.

You’d need to clean the air filters and change the thermostat or heater core to fix all these.

Leaky Radiator

One of the main reasons your car heater isn’t working is leakage in the radiator.

Your vehicle works with a radiator that eliminates heat from the engine, giving a smooth and calm ride without damaging the parts.

The leakage in the radiator drains the water causing damage to the engine. The radiator cools down the heated parts and gives energy to the parts to function efficiently.

With a leak in a radiator, the potential damages would cause the car heater not to work correctly, ultimately damaging other parts of the vehicle.

Excess of anything is trouble.

If your vehicle is overheating, it may easily damage the engine, thermostat, and cooling system, eventually making your car heater not function efficiently.

There can always be a leak in the radiators; therefore, it is mandatory to check in every time before you leave.

A leak in the radiator can be caused by rust, excessive heat, a bad Thermostat or heater core, and pressure.


To avoid leakage in the radiator, make sure to check the water to avoid overheated engines even in winters.

If all these solutions are still ineffective, it’s good to show your car to your nearest mechanic.

How To Avoid These Issues From Occurring?

There are some factors to be mindful of to stop these issues of why your car heater isn’t working, as these problems won’t just fade away with a blow.

After purchasing a vehicle, it is your responsibility to take good care of it.

Regular cleaning and maintenance would keep your components and parts of the vehicle in good shape and properly held together.

Some issues might be technical, and some might be because of extreme pressure on the components causing them to rust out or get damaged completely, eventually making your car less functioning.

To avoid these issues is to take good care of your vehicle. Take your car for regular trips to the mechanic for upgrades and maintenance.

These issues won’t often occur by regulating and keeping your vehicle updated.


We have discussed the possible problems or troubleshoots why your car heater isn’t working.

The most rational solution of all these is to take your vehicle to a trusted mechanic with an excellent background to help you fix your heater so that you can drive safely and efficiently in cold weather.

After analyzing your issue, tell your mechanic or have them analyze the issues and fix the problems so that you can drive warmly and safely.

After all, we all love driving in a warm car in cold weather.