It is no fun when you reach for your car heater in the dead of winter and all you get is a blast of cold air. The 2001 Ford Focus heating system is a pretty simple set-up. Heated coolant flows through a heater core and an electric fan blows air over the core. Heated air is then blown through vents into the vehicle itself. As with most heating systems, it can sometimes break down with wear and tear. Before taking your vehicle in to the shop for an expensive repair, there are a number of things you can troubleshoot.
Check to see that your radiator has enough coolant. Air can get trapped in the hoses if there is not enough coolant in the system and this can impede heat flow. Check the inlet and outlet hoses connected to the heater core to make sure that the coolant is circulating correctly. If both hoses are not hot, there could be a problem with coolant circulation and it may be time to replace the heater core. Have a mechanic check this problem out for you.
Check the fuse box for any blown fuses. Check the fuse schematic on the door of the fuse box to find the fuse related to the heater. Replace any damaged fuses with others of the exact same amperage.
Check to see that air is flowing across the heater core. Switch the heater to the maximum heat setting as well as the highest fan setting. If you do not hear the fan blowing, then the fan could be defective and may need to be replaced.
Check to see if the thermostat is stuck in the open position. Start the vehicle when the engine is cold, then place your hand on the upper radiator hose. If the thermostat is stuck open, you will feel the coolant flowing through the hose immediately. Under normal operation, the coolant will only begin to flow once the engine begins to warm.
Feel the carpet area of the passenger-side floor for any wetness or a strong, sweet odour. This could mean that the heater core is leaking and may need to be replaced.
If new fuses continue to blow, the circuit could be overloaded. If the fuse blows immediately, the cause could be a short in the system. Have a mechanic check the electrical system for both problems. Coolant is used to cool the engine as well flow through the heater core to heat the inside of the vehicle. Make sure that no hoses have come loose or are damaged. If a hose connected to the heating system has a kink in it, hold the hose between your thumb and forefinger and bend it the other way until the kink has popped out. Take care not to touch the hoses when the engine is hot. If you do not hear the fan blowing, it could also be an electrical problem. Have a car electrician check your system out. If the heater core becomes clogged, the only fix is to replace the core.