CVO 4/15/2011Advice: If the vehicle that you are working on has a heater control valve, it will be installed in one of the heater hoses. Not all cars have a heater control valve. Locate the heater hoses and follow along their lengths. If you do not find a heater control valve, don't worry. Most modern vehicles Use blend doors in the heater box to turn the heat on and off.
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