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Q: Won't blow heat on the inside

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The heat will not blow on the inside the thermostat has been changed and the heater core has been flushed. What do I need to do?
My car has an automatic transmission.

You should start and run engine for at least 5 minutes at 2000 rpms to warm the engine up to full operating temperature. Set heater on medium blower speed and measure vent temperature as temperature is increased with controls. If there is no temperature change at all then the most common cause is the temperature control actuator on the heater a/c temperature blend door. Replace the actuator and check door operation when actuator is off to be replaced. This checks door operation.

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