Your truck’s heating system consists of various heavy-duty HVAC parts that blow hot air through your vents and heat your cabin. This works by heating the coolant, circulating the cooling system through the radiator to bring down the temperature, and having the coolant pass through the heater core inside your dashboard.

A defective heater in your truck caused by a single damaged part can make even a short trip a nightmare. The key to fixing your heavy-duty vehicle heating system and keeping yourself comfortable throughout your ride is to first figure out the root cause of the issue.

To help you diagnose the problem, here are some of the most common reasons for a truck heater to malfunction:

A stuck or malfunctioning thermostat

The thermostat of your truck’s heater is responsible for controlling the coolant flow through the radiator. When it gets stuck or malfunctions, your coolant will keep circulating through the radiator and stay cold. You can identify if your defective heater’s issue is your thermostat if it is stuck in the same place all the time regardless of the amount of time your engine has been running. Fortunately, the issue is easily fixed with the installation of a new thermostat or the assistance of a reliable service provider specializing in heavy-vehicle problems of all sorts.

Low coolant level

Cold air blowing out of your vents for the first few minutes after you turn on your heater is considered normal. If it fails to warm up, though, then you might have an insufficient amount of engine coolant. To fix this, fill up your engine coolant right away. Remember—your engine might overheat when you have a coolant leak that can cause costly repairs, so make sure to pay proper attention to your coolant levels every time you open the hood.

A leak

A leak from any part of your engine where the coolant travels through can cause your coolant levels to get too low and hinder your heating system from working as it should. Fix this by looking for a leak in your water pump and hoses. You can also count on a reliable mechanic to have your radiator repaired or replaced in no time.

Deteriorated coolant hoses

Your truck is subject to wear and tear and ageing over time, and this can cause your coolant hoses to get worn-out. As a result, they can get clogged or have loose clamps. As soon as you notice any signs of wear or leaks, make sure to replace your old coolant hoses right away.

Clogged heater core

The heater core of your truck absorbs the heat and sends it through the vents as the coolant travels through the passageways. These paths can rust or get clogged when they become filled with dirt, dust, and debris, preventing warm coolant from passing through. You can flush them to clear out the passages or have your heater core replaced altogether.


Your truck’s heater is essential to your comfort, safety, and productivity, which is why it needs proper care, attention, and maintenance. When it gets broken, don’t forget the common causes listed above and reach out to a mobile servicing and support company for professional help.

At Simplicity Air, we install and service heavy-duty equipment heating for on-road and off-road vehicle owners in Southern Ontario, Windsor, Ottawa, Niagara, and the surrounding areas. Contact us today to request service!

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