Troubleshooting Car Heating Problems

Now that winter is here, having a working car heater is essential to any drive around town. There’s nothing like turning on the car heater to find cold air coming out and having to drive to work shivering. Worse, you could find out that your car heater isn’t working right before leaving for a long road trip. Before you bundle up for the road, try troubleshooting car heating problems to save yourself a cold drive!

Troubleshooting Car Heating Problems

Car heaters work by blowing the heat which is naturally produced by car engines through a heater core and into the cabin of the vehicle. Like other components in your vehicle, there are many potential causes for car heaters to stop blowing warm air.

The first thing to determine when troubleshooting car heating problems is whether warm air is available to be pumped into the vehicle. Heat being ‘available’ refers to whether or not heat can move from the engine compartment into the cabin. Troubleshooting car heating problems only takes a few minutes and can save you time and unnecessary trips to the mechanic.

First, start the car and let it get warm. Your heater relies on hot coolant flowing through the heater core, so this step may take 5 – 10 minutes to heat up depending on the age of your vehicle. Once your car has heated up, turn on your heater and fan to their maximum settings.

The next step will depend on whether or not you feel heat coming out of the vents.

Heat is Flowing Through the Vents

If you do feel heat from the vents, even if just a weak stream, then the issue could be a blown fuse or a malfunctioning fan. To troubleshoot a car heater when heat is flowing through the vents, follow these steps:

Listen to hear if the fan engages. If you don’t hear the fan engage, the issue could be a broken fan or a blown fuse.
Check to see if the fuse is blown. Your vehicle’s owner’s manual will show you where the fusebox is located as well as which fuse you’ll need to check. Most cars come with spare fuses, but in case yours does not, they are easy to get at your local auto supply shop. Just make sure that the fuse is rated for the correct amperage. This detail will also be located in your owner’s manual.

Heat is Not Flowing Through the Vents

If you don’t feel any heat coming out of the vents, then the problem could be low coolant levels, water pump problems, or a broken thermostat. Other issues may include damaged or dented hoses in the vehicle’s cooling system or a malfunctioning gate on the heater duct. To troubleshoot a car heater when heat is not flowing through the vents:

Check your coolant levels. If they’re low, fill up your coolant (it’s important to do this only when the car is cool). Wait for the car to heat, then try to use the heater again.
If refilling the coolant does not fix the problem, then the heating issue may be more severe. Water pump issues and broken thermostats may need to be looked at by your mechanic to diagnose and repair.

You might be thinking that with enough gloves, scarves, and coats, you can tough out the winter without a working car heater. But heaters are important to your vehicle’s overall safety and visibility too. Your windshield defroster relies on warm air to keep the glass clear.