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Q: Heater blows cold air

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My car’s heater does not blow out hot air. I have flushed the heater core and checked both ends of the radiator, and the hoses get hot. If I turn off the air and let it sit for a few minutes then turn it back on I get hot air the first couple of seconds. But then it gets cold. Do you know what might be causing this and how I can fix it?

Hello. The Heater/AC control panel utilizes vacuum (from the engine) to actuate the hot water control valve - regulating heat from the heater. A vacuum leak, bad hot water control valve, or the heater control panel itself may have failed. If you would like to have this inspected, a certified professional from YourMechanic can come to your car’s location to have the AC system diagnosed.

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