Q: no heat coming out of heater

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radiator full of water / hoses going in and out of heater core are hot / fan works / How do I diagnose heater actuator what fuse do i check also
2004 chevy express 3500 6.0 motor

My car has 250000 miles.
My car has an automatic transmission.

Hello, thank you for writing in. Check the radiator hoses as well, and make sure both are warm if not hot. If the engine itself is running too cold, by the time the coolant gets to the heater core it is even colder. To check the blend door actuators, you will need to remove the glove box and most of the dash to access them and the main unit. You will highly benefit with a repair manual that walks you through the procedure if attempting at home. With that being said, you should rule out your switch and the engine temperature first. The fuse box in the engine compartment under the hood will have some HVAC fuses, and should be #21 or #22. For more help resolving the issue, contact our service department to schedule an appointment.

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