The heater core is a small radiator-like component located inside the vehicle's cabin, typically behind the dashboard. It is responsible for transferring heat from the engine's coolant to the air that warms the cabin. The engine coolant, which absorbs heat from the engine, flows through the heater core. When the blower fan pushes air over the heater core, the air is heated and directed into the cabin through the vents.

Heater cores are usually made of aluminium or brass and consist of small tubes and fins to maximise heat transfer. They are a vital part of the vehicle's cooling system, as they help regulate engine temperature while providing warmth to the occupants.

Signs of a Faulty Heater Core

A malfunctioning heater core can lead to several issues. One common symptom is a lack of warm air from the vents, even when the heater is turned on. Other warning signs include a sweet smell of coolant inside the cabin, fogged-up windows, or coolant leakage under the dashboard. Ignoring these signs can lead to more significant problems, such as engine overheating or coolant loss.

What is a Heater Fan Resistor?

The heater fan resistor is an electrical component that controls the speed of the blower fan in the heating and air conditioning system. It works by regulating the amount of electrical current that reaches the blower motor. This allows the fan to operate at different speeds, which can be adjusted using the fan speed control on the dashboard.

Most modern vehicles use a resistor pack with multiple resistors to achieve various fan speeds. The resistor is typically located near the blower motor, making it relatively easy to access and replace if needed.

Common Issues with Heater Fan Resistors

A failing heater fan resistor can result in the blower fan working only at certain speeds or not functioning at all. If the fan only operates at its highest speed, it is often a sign that the resistor has failed. In some cases, the resistor may overheat and cause damage to the wiring or connector, which can lead to more extensive repairs.

Maintaining Heater Cores and Fan Resistors

Regular maintenance of the vehicle's cooling and heating system can help prevent issues with the heater core and fan resistor. Flushing the coolant system at recommended intervals can reduce the risk of blockages in the heater core. Additionally, inspecting the blower motor and resistor for signs of wear or damage can help identify potential problems early.

When replacing a heater core or fan resistor, it is essential to use high-quality parts that are compatible with the vehicle. As access to these parts can involve significant disassembly of the dashboard it pays to use quality products from Repco to ensure reliability and longevity.