Could be,a stuck open thermostat,low on coolant,plugged heater core,faulty temp blend door actuator,
Heater control valve stuck open. Possible blend air door failure.
There are several possible causes. A thermostat stuck open A heater control valve stuck closed A malfunctioning blend air door (located in the heater box) Low coolant level Malfunctioning heater controls
Sounds like a stuck blend door.
If you can turn on the heater but only cold air comes out you should check the blend door. It controls the door to switch from cold air to hot. It sits directly behind the heater/AC controls. It is white square plastic piece (approx 3in x 5in half inch thick and has a plastic screw rod that attaches to the heater/AC controls and they strip out.AnswerIt could also be referring to being stuck on defrost vents...See "Related Questions" for extensive information about changing the temperature blend door actuator motor and defrost only problems
Hi, It is not the blend door, that is for heat/cold changes. The mode door could be the problem, or stuck defrost door.
Low on coolant, stuck open thermostat, plugged heater core, faulty temperature blend door,
The blend door is probably stuck.
Assuming the blower is working, the reason for no heat could be, low on coolant due to leak in coolant system, thermostat stuck open, heater core plugged or temperature blend control NG.
1. heat control linkage disconnected or broken or vacuum source problems(low vaccum source or broken vacuum lines) 2. heater unit doors stuck or non functioning heater door actuators
Low on coolant. Stuck open thermostat. Plugged heater core. Faulty temp blend door.
This sounds like a temperature blend door problem - with the door stuck in the heat position. See "Related Questions" below for information on Taurus/Sable blend door actuator motors and blend doors
Low on coolant. Stuck open thermostat. Plugged heater core. Temp blend door inop.
Low on coolant. Thermostat stuck open. Heater core plugged up. Temp blend door malfunction.
The blend door could be sticking on the truck. The vacuum system could have a leak. Or the cables to the heat valve could be malfunctioning. Check these three areas to fine why your heater is stuck on hot.
The heater control valve is used to shut off hot coolant from entering the core when the heater is in the off position. A heater control valve can be actuated by either a vacuum line or a cable from the vacuum heater control valve to the heater core. This hose should be warm; if not the heater control valve is stuck and needs to be replaced
Little or no heat from heater/defrost if t-stat is stuck open. Engine overheats if t-stat is stuck closed.
It sounds like your air flow diverter is stuck on defrost. Basically it is a little door that diverts the air fom vent to defrost to feet. It could be either the heater control valve, or te temperature selecter cable is broke.
The HVAC doors that control the airflow are activated by small vacuum motors. The system is designed to fail safe; this means that the system will fail in full defrost mode. So, knowing this and the fact that you have heater but no A/C or defrost you should assume the system has a failed control head (the part that you select functions with with button or lever). Or the doors are stuck due to an warped duct system (usually high heat related).
You may be low on coolant, or the thermostat is stuck open, or the heater core is plugged up, or the temp blend door is broken.
The Blend Door Actuator is stuck or has failed. Somewhat of a common issue.
Thermostat is missing or stuck open, coolant level is low, heater core is plugged or heater control valve is stuck closed.
Could be, Stuck open thermostat, Low on coolant, Plugged heater core, Temperature blend door actuator malfunction.
Could be, low on coolant, stuck open thermostat, plugged heater core, faulty temp blend door actuator,
Your air mix door is stuck, follow the cable from the temp control to the heater/ac unit and see if the flapper is moving, if not the door itself may be stuck or broken and you'll need to get in there and replace it.