When the temperature dips, your vehicle’s heater is your best friend, so it’s important to make sure the system is operating properly.
Automotive heaters consist of several main components – the vents, the blower fan and the heater core. If any of these fail, you could be left cold and miserable on your commute.
The cooling system circulates coolant around the engine to draw off excess heat so the engine doesn’t turn into a lump of molten metal. The hot coolant passes through two heat exchangers to transfer the heat to the air flowing around the vehicle. One of these is the radiator, which handles most of the work of cooling the engine. Before the hot coolant gets to the radiator, it passes through a smaller heat exchanger behind the passenger side of the dashboard.
The most important part of heating system maintenance is making sure the cooling system is flushed regularly and the hoses are in good condition. If this step is ignored, the heater core and radiator can corrode or the passages can get clogged, preventing proper circulation.
The first step in testing the heater is to make sure the engine is thoroughly warmed up and the temperature control is turned up. With the engine warm, you should feel warm air coming out of at least some of the vents. If not, the cooling system should be checked for leaks, blockages and low coolant level. Be sure to check your thermostat for proper operation. If coolant is dripping into the passenger footwell, the hoses and heater core should be tested for leaks.
If heated air is available, the fan should be checked to make sure it works at all speeds levels. Direct the airflow to the dashboard vents and turn the fan up to ensure each speed level works. If the fan doesn’t work, it could be a burned out motor or a blown fuse. If the fuse has blown, the fan and motor should be checked anyway to make sure there are no obstructions causing an overload. If the fuse is fine, the motor and wiring should be checked.
Even if the wiring is intact and delivering power to the fan motor, it may not blow air if a bearing has failed or something is blocking the fan, such as a small animal looking for a warm place to sleep. If the fan is working but air still isn’t blowing, it’s time to check the ducts. If air blows from the dash vents when the airflow is set to circulate but not when directed to take in fresh air, check the intake at the base of the windshield. Leaves and other debris often collect there behind the rear edge of the hood.
If the air doesn’t move even in recirculation mode, the flaps inside the ductwork that direct airflow may not be functioning. On most vehicles, the doors that manage the mix of warm and fresh air or send the air to your feet, windshield or dash are vacuum operated. If the air can’t be re-directed, it’s time to check the vacuum hoses from the engine and the heater control valve. Some newer vehicles are now using small electric servo motors to move these flaps, so if the direction and blending don’t work, it’s time to check the fuses again. If the fuses are intact, a technician will need to check the wiring and the motors.
In general, heating system diagnosis and maintenance is not that complicated. If the cooling system is properly maintained to preserve the engine, the heater will usually work most of the time. Test the fan, temperature and directional controls on a regular basis and if necessary, get the system repaired promptly before you really need it. Stop by today and let us take care of your heating system to ensure it works when you need it most.