No one wants to drive a car with a malfunctioning heating system in the middle of winter. When it happens, you need to quickly get to the source of the problem so that you can operate the vehicle comfortably for the rest of the season. Here’s how to determine which component may be causing the headache and whether you need to visit an auto shop for repairs. 

How Does a Car Heater Work?

When a vehicle reaches operating temperature, the engine thermostat opens and allows coolant to flow through the system and transfer any heat from it to the radiator. From here, the heated fluid passes through the heater core—a small radiator located in the cabin dashboard. A blower fan then directs the heat into the passenger compartment. 

What Are Some Common Reasons the Heater May Not Be Working?

Low Coolant

When the coolant reserves are running low, there’s still often enough fluid to run at the correct operating temperature. However, there might not be enough to reach the heater core, which sits up higher than the engine.

If your car interior isn’t heating up after a few minutes, check the coolant levels inside the reservoir, which should have a full and low mark on the side of the tank. Wait until the engine is cool before adding more. If you aren’t sure which type of coolant is currently in the reservoir, head to an auto shop, as mixing types can create sludge in the radiator.

Broken Blower Components

If the heater only blows air on the highest fan setting, the blower motor control module probably needs to be replaced. However, if the fan doesn’t produce any air, the blower motor may be damaged. In this case, you’ll need to contact a professional auto shop to have it repaired or replaced. 

Clogged Heater Core

If there’s plenty of coolant, but the air is still coming out cold, the fluid may be having problems reaching the heating core. This usually indicates a clog—caused by corrosion, improper use of stop-leak products, or bad coolant—in the small brass or aluminum tubing that moves the coolant in and out.

If so, it will cause the interior of the cabin to fog up and produce a fruity odor. You might also notice the car temperature going higher than normal. Visit a mechanic to determine if the blockage can be cleared or if the heater core needs to be replaced.

If your car’s heating system isn’t working correctly, visit Craig’s Towing & Repair in La Crosse, WI, for a solution. This full-service, family-owned auto shop provides a wide range of work, from general maintenance to major repairs. They’re AAA®-certified, and their expert mechanics are trained to deal with any issues on most makes and models. Call (608) 784-1638 to schedule an appointment, or visit their website to learn more about their services.