When you live in the Twin Cities and own a vehicle, having a properly functioning heater is a must. If your heater suddenly starts blowing lukewarm or straight cold air, your commute won’t just feel miserable; it can actually be quite dangerous.


A nonfunctional heater can’t keep your windshield free of condensation and ice, a hazardous situation for any driver. And from a comfort standpoint, a long commute in a frigid vehicle can be almost unbearable. So what might cause your heater to stop blowing warm air? The auto mechanics at AA Auto Tech share a few common culprits below.


Low Coolant Level or Contaminated Fluid

Your coolant reservoir contains a mixture of antifreeze and water, which serves to prevent the engine from freezing or overheating. It also ensures the excess heat from the engine transfers to your heater core so it can blow warm air into the cabin. If the fluid level in the reservoir is too low, your heater may stop blowing warm air, or worse, your engine could freeze.


When the water-antifreeze ratio isn’t quite right, whether due to evaporation or fluid contamination, your coolant becomes more susceptible to freezing. When that happens, your heater will blow cool air and ultimately, your engine can overheat.


To find out if fluid contamination or low coolant levels are the culprit behind the cool air coming from your heater, take your vehicle to an auto mechanic as soon as you can. You may need a radiator flush to solve the problem.


Heater Core Problems

The heater core creates the warm air that, blows into the cabin of your vehicle with the help of the blower fan. It contains an intricate network of tubes that can be susceptible to leaks and clogging, and when those issues develop, they can reduce the amount of coolant inside your system.


Often, vehicles that have contaminated coolant or low levels of fluid also have issues with their heater cores. Together, the two issues can cause the system to blow out cool rather than warm air. Other signs you may notice if you’re dealing with a faulty heater core include:


●        Puddles developing under the dashboard or on the passenger-side floor

●        Windows that fog up more than usual

●        A sweet-smelling odor inside the vehicle cabin


To find out whether your vehicle’s heater core is causing the problem, have it diagnosed by a qualified auto mechanic. Since several issues can cause your heater to blow warm air, the only way to pinpoint the problem is through a professional assessment.


Non-Functional Blower Fan

If your heater appears to be blowing warm air but the airflow through the vents is almost non-existent, a faulty blower fan is likely the culprit. Since the blower fan’s primary job is to ventilate warm air from the heater core into the cabin of your vehicle, if it’s not working, that air cannot flow into your car or truck.


Electrical Issues

If your heater stops blowing air altogether or if it starts and stops intermittently, your vehicle likely has an electrical issue. Frayed or loose wires or a blown fuse can easily cause your heater to fail, and both issues are easy to fix.


But certain electrical issues that can lead to heater malfunction can be much more complicated and difficult to diagnose. Regardless of the assumed severity or complexity of an electrical problem, only a qualified auto mechanic should diagnose and repair these types of issues.


AA Auto Tech: Your Twin Cities Source for Comprehensive Auto Repair and Maintenance

If your heater has stopped blowing warm air or is experiencing any other performance issues, bring your vehicle to our team at AA Auto Tech. For over 25 years, we’ve specialized in full-service preventative maintenance and comprehensive auto repair and are proud to serve the entire Twin Cities metro area. To schedule an appointment, feel free to contact us online or give us a call at 651-437-2218.