The connector hose heater control valve is the valve that allows hot coolant from the engine to flow into the heater core. The heater core is mounted inside the vehicle, positioned near the blower motor and provides the warmth for hot air to be blown through the vents when the heater is activated. When the heater hose control valve or any of its hoses or connectors fail, it can cause problems for the rest of the cooling system and vehicle. Usually a problem with the heater control valve or any of its associated components will produce a few symptoms that can alert the driver of a potential problem that should be serviced.
No warm air
One of the first symptoms of a problem with a heater hose control valve or any of its associated components is an inoperable heater. If the heater control valve fails or gets stuck, it will not be able to allow hot coolant into the heater core so that the heater can operate. If the heater does not have hot coolant the AC system will not be able to blow hot air, and the front defroster may not work.
Another symptom of a problem with the heater control valve or it’s hoses or connectors is a coolant leak. If the housing cracks or breaks due to old age or corrosion coolant will leak out. Old age and corrosion can also cause the heater hoses and clamps to leak as well. A coolant leak at the heater control valve is not only a problem in that it will disable the heater, but it will also compromise the cooling system which can cause the engine to overheat. Coolant leaks can appear as small leaks, spouts of steam, or in more serious cases, large puddles.
The heater control valve and its associated parts are simple components, however, they are very important to the proper functionality of the heater, and any problems with it can both disable the heater as well as cause other problems for the vehicle. If you suspect that your heater control valve or any of its associated components is having an issue, have the vehicle inspected by a professional technician. They will be able to determine if the car needs a heater control valve replacement, or if a different repair is needed.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Connector Hose Heater Control Valve and was authored by Ed Ruelas.