Why Is My Car Blowing Cold Air When The Heat Is On?

Why is the heater in my truck blowing cold air?

So if your heater is blowing cold air it’s because: 1.

There’s no hot coolant flowing into the heater core.

It could also be something simple like the valve that turns on the flow of hot coolant into the heater core is stuck, or the linkage between the switch on your dashboard and the valve itself may be broken..

What do I do if my heater is blowing cold air?

When your furnace blows cold air, try turning the heating unit off and on. If the air feels warm for a moment or two, then switches to cold, it may be that the flame sensor is dirty. With a dirty flame sensor, your gas burner won’t stay lit, causing the air to go cold soon after the furnace turns on.

Why is my heater not blowing out hot air?

AUTO ensures that the blower will run only when the furnace heats the air. Your furnace may be blowing cold air because the filter is too dirty. … When overheating, your furnace can trip a high limit switch, causing the furnace burners to shut off so that the heat exchanger does not crack.

What are the symptoms of a bad thermostat?

There are several common symptoms associated with a bad or failing thermostat that will alert you that service is due.Temperature gauge reading very high and engine overheating. … Temperature changing erratically. … Coolant leaks around the thermostat housing or under the vehicle.

Does hot air go out or cold air come in?

Cold air flows downward according to hot air because it is more dense and sinks while hot air rises. In hot room the air will be much thinner thus reducing the pressure so the air flows from cold room to hot rooms. Cold air sucks out the energy of hot air!

Why is my heater not working?

Thermostat malfunctions cause most heating system failures. Other causes include a tripped circuit breaker or blown fuse, or—in the case of combustion furnaces—a pilot light that has gone out. If the heat doesn’t come on even when you adjust the thermostat above room temperature: … Or replace the fuse.

Why is cold air blowing when the heat is on?

Your furnace may be blowing cold air because the filter is too dirty. A dirty air filter blocks airflow over the furnace’s heat exchanger, causing it to overheat. When overheating, your furnace can trip a high limit switch, causing the furnace burners to shut off so that the heat exchanger does not crack.