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How to Fix It When Your Car Heater Isn't Working
Try these troubleshooting steps to get your heater working again
By Jeremy Laukkonen Jeremy Laukkonen Writer Shoreline Community College Jeremy Laukkonen is automotive and tech writer for numerous major trade publications. When not researching and testing computers, game consoles or smartphones, he stays up-to-date on the myriad complex systems that power battery electric vehicles . lifewire's editorial guidelines Updated on July 26, 2021 Reviewed by Christine Baker Reviewed by Christine Baker Christine Baker is a marketing consultant with experience working for a variety of clients. Her expertise includes social media, web development, and graphic design. lifewire's editorial guidelines Tweet Share Email Tweet Share Email Connected Car Tech Android Auto Apple CarPlay Navigation To fix your car's malfunctioning heating system, you first need a basic read of the situation. Is the heater blowing cold air into the car, or is the car heater not blowing any air at all? Lifewire / Maddy Price Why a Car Heater Stops Working
If cold air is coming out of the heating vents even when the vehicle is warmed up and the thermostat is set to hot, you could be dealing with one of the following problems: Low coolant.A blockage in the heater core.A stuck blend door.A stuck heater valve.A bad switch or linkage. If the heater isn't blowing any air, the problem is likely a faulty blower motor or electrical connection. How to Fix a Car Heater That Isn' t Working
These instructions will help you diagnose and fix a car heating system that blows cold air. If the heater isn't blowing any air, skip to the next section. Check the coolant level. Turn off the vehicle and let the engine cool completely. The coolant is housed in a translucent plastic jug in the engine compartment. It should have level indicators that show how full or empty it is. If the coolant level is low, the vehicle likely isn't circulating enough antifreeze through the heater core, and it needs to be replenished. Adding coolant might fix the problem in the short term. However, low coolant often indicates another problem, such as a leaking gasket or hose. If the vehicle burns coolant, it may have a blown head gasket, which can be costly to fix. Dark brown coolant indicates rust in the cooling system. Check the heater core temperature. Lift the hood and check the temperature where the heater core hoses enter the heater core box. The safest way to do this is with a non-contact infrared thermometer. If one hose is the same temperature as the coolant and the other hose is cold, a blockage might exist in the heater core. If the vehicle has a valve in one of the hoses, check its operation. A stuck valve prevents coolant from flowing through the heater core. Check for debris in the heater box. If you determine that hot antifreeze flows through the heater core, debris such as leaves, pine needles, and road debris might be stuck in the heater box. Switch the thermostat from hot to cold and listen. If you don't hear the blend door moving, the problem might be the blend door, linkage, wiring, or the thermostat switch, depending on the vehicle. How to Fix a Car Heater That Isn' t Blowing Any Air
If the heater isn't blowing any air, a faulty blower motor or electrical connection might be the problem. Follow these steps to fix it. Check if the blower motor receives power. The only way to determine which component has failed is to grab some basic diagnostic tools, access the blower motor, and check whether it receives power. The specific diagnostic procedure varies with the vehicle. If it receives power, check if the blower motor is burned out. After removing the blower, you might find a squirrel cage so clogged with debris that the motor can't operate. In other cases, a broken wire, rusted connections, or a disconnected pigtail assembly might be the issue. If the blower doesn't receive power, check that the blower fuse isn't blown. A blown fuse often indicates an underlying problem, so never replace one with a larger fuse to prevent it from blowing out again. If you replace a blown fuse with one of the same amperage and it doesn't go out, the fuse likely failed due to age. If the original fuse is not blown, trace the problem to the source by testing the resistor, relay, and switch. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire How to Fix a Stuck Car Window How to Fix a Car Horn That Won't Stop Honking How to Fix It When a Keyboard Won't Type Finding a Cheap Fix for a Broken Defroster When Your Car Heater Blows Cold Air 5 Fixes for a Broken Car Heater Headlights Not Working? Try These Fixes Block Heaters vs. Remote Starters: Which One is Best? What to Do When the Gauges in Your Car Aren't Working Why Your Car Won't Start Even Though the Lights Work Do Electric Vehicles Use Oil? What to Do When Your Car Radio Won't Turn On How to Fix it When Your PS4 Is Overheating Is There a Real Alternative Car Heater? How to Fix Common Car Amp Problems How to Fix It When an Xbox One Controller Headphone Jack Isn't Working Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies