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When temperatures drop, a working car heater is essential, not only for comfort, but for safety. A functioning heating and HVAC system helps with demisting, visibility, and cabin warmth. If your car heater stops working in winter, it can quickly become a frustrating and potentially dangerous issue for UK motorists.
At Drift Bridge Group, our Audi, Volkswagen and Honda dealerships diagnose and repair hundreds of winter heating faults every year. This guide explains the most common causes and the solutions available.
1. Low or Leaking Coolant
Coolant regulates engine temperature and supplies heat to the cabin via the heater core. If levels are low, the heater cannot produce enough warm air.
A technician will check for leaks, top up coolant with the correct manufacturer-approved mixture and ensure the system is pressurised correctly.
Audi, Volkswagen and Honda engines require specific coolant types, available at all Drift Bridge service centres.
2. Heater Core Blockages
Over time, sediment can build up inside the heater core, restricting coolant flow and reducing heat output.
A professional heater core flush or replacement may be required.
3. Faulty Thermostat
If the thermostat is stuck open, your engine will not reach its proper operating temperature, meaning there is no heat to send into the cabin.
Replacing the thermostat is an affordable and effective solution.
4. HVAC Blower Motor Problems
The blower motor pushes warm air through the vents. If it fails, you will not feel airflow even if the system is producing heat.
Modern Audi, VW and Honda models use electronically controlled blower motors that should always be diagnosed using manufacturer-approved equipment.
5. Damaged Climate Control Sensors
Premium models such as the Audi Q5, Volkswagen Tiguan and Honda CR-V rely heavily on digital climate control. If a sensor or actuator fails, the system may blow cold air or distribute heat incorrectly.
Specialist diagnostics will identify faulty sensors or actuators for repair or replacement.
6. Blocked Cabin Air Filter
A dirty cabin filter restricts airflow, making the heater seem weak even when everything else is working.
A simple cabin filter replacement restores proper ventilation and improves air quality.
7. Electrical Issues and Blown Fuses
Heating systems depend on electrical components. A blown fuse, wiring issue or faulty switch can prevent the heater from activating.
Drift Bridge technicians can perform quick electrical diagnostics to locate and resolve the issue.
8. Frozen Components in Extremely Cold Weather
In very low temperatures, moisture can freeze inside valves, actuators or external air flaps.
Allow the car to warm gradually. Avoid switching the heater to maximum immediately after start-up, as this increases stress on the system.
When should you visit Drift Bridge Group?
Book a winter heating and HVAC check if you notice:
Our expert teams at Epsom Audi, Walton Audi, Drift Bridge Volkswagen and Gatwick Honda use genuine parts and manufacturer diagnostics to repair heating and HVAC systems for all models.
You can book all these checks at:
Final Thoughts
A faulty heater is more than an inconvenience. It can reduce visibility, affect engine performance and compromise safety. By identifying the signs early and booking a professional winter check, you can avoid more serious issues and stay warm, safe and comfortable throughout the cold months.