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Shawn
Shawn, Auto Service Technician
Category: Ford
Satisfied Customers: 3756
Experience:  16 years experience Ford,Nissan and Honda dealership in all areas
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1997 Ford Expedition: my lower coolant..radiator hose..heater core

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I have a 1997 Ford Expedition and I have no heat. Also my lower coolant/ radiator hose doesn't get hot so I was thinking maybe it's the heater core? I brought it to a local shop and they said it was the heater control switch which I'm having a hard time believing but I could use some help form a trained Ford Tech. plz help. thank you.

HiCustomer

 

 

Thank you for asking your question on JustAnswer. The most common cause of the problem you are having is a defective Temperature blend door actuator. (CLICK HERE FOR INSTRUCTIONS). Hope this helps you out.

 

Before replacing the Blend Door Actuator, make sure cooling system is full and there are no air pockets trapped in the system, also while the engine is running make sure both heater hoses are very hot, if one is cooler than the other suspect a plugged or restricted heater core.

 

If the hoses are only getting warm, (must be very hot) suspect a defective thermostat, as long as there is no air in the cooling system.

 

Make sure that there are no leaks also, any leak will lead to poor heating performance as well.

 

 

 

A/C Electric Blend Door Actuator

 

The A/C electric blend door actuator is located on the plenum assembly.

  • Its function is to move the air temperature blend door on command from the control assembly.
  • The A/C electric blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate the position of the air temperature blend door.
  • A 5 volt signal is applied to the ends of the potentiometer. The voltage available at the wiper indicates the position of the potentiometer. The expressed value of the actuator wiper voltage is sent to the EATC module and is compared to the desired wiper voltage determined by the EATC module. The control module then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the desired wiper voltage.

 

 



Thank you again for trusting us with your problem. Please reply as soon as possible so that we can finish answering your question.



Edited by Shawn on 3/2/2010 at 11:39 PM EST
Customer: replied 7 years ago.
The cooling system is full. and yeah the upper hose gets warm/hot and the lower hose is cold even after a long drive. I changer the thermostat already...so where do I go from here?

HiCustomer

 

 

Thank you for asking your question on JustAnswer.In your original statement you said one hose is cooler than the other, make sure cooling system is full and there are no air pockets trapped in the system, also while the engine is running make sure both heater hoses are VERY HOT, if one is cooler than the other suspect a plugged or restricted heater core.

 

 

 

If the hoses are only getting warm, (MUST BE VERY HOT, TOO HOT TO TOUCH) suspect a defective thermostat, as long as there is no air in the cooling system.

 

 

 

Make sure that there are no leaks also, any leak will lead to poor heating performance as well.

Customer: replied 7 years ago.
How would I clear the Heater core? or does it have to be replaced? It's not leaking that I know for sure the passenger side rug isn't wet. and If i don't replace it what could happen?
Heater core is inexpensive and should only be replaced. Over time the heater core will begin to leak and unfortunately will leak into the interior passenger area over time. Therefore causing an even bigger problem.
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