How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Kenny Z. Your Own Question
Kenny Z.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5388
Experience:  Auto Trans, Drivability and Electrical Specialist
Type Your Ford Question Here...
Kenny Z. is online now
A new question is answered every 9 seconds

I am working on my friends 2001 ford expedition. The heater

This answer was rated:

I am working on my friends 2001 ford expedition. The heater blows but not hot air. I read the articles on this website and think I know what the problem is but dont know how to troubleshoot it further. The thermostat is working properly, it is full of coolant, and the outlet heater hose is only slightly cooler then the inlet at the firewall. But, the A/C clutch will not disengage. With the heater on, the A/C is still on. The A/C lines are very cold and are even showing frost on the outsides of them. I pulled the A/C clutch relay and it disengaged and the A/C lines warmed up. My theory is because the A/C will not disengage by use of the dash controls the hot water is being diverted from the heater core. This is were I am stuck, I dont know where to go from this point. Any help would be greatly appreciated. Jerry
Customer: replied 8 years ago.

2001 Ford expedition 4.6

Already Tried:
I am working on my friends 2001 ford expedition. The heater blows but not hot air. I read the articles on this website and think I know what the problem is but dont know how to troubleshoot it further. The thermostat is working properly, it is full of coolant, and the outlet heater hose is only slightly cooler then the inlet at the firewall. But, the A/C clutch will not disengage. With the heater on, the A/C is still on. The A/C lines are very cold and are even showing frost on the outsides of them. I pulled the A/C clutch relay and it disengaged and the A/C lines warmed up. My theory is because the A/C will not disengage by use of the dash controls the hot water is being diverted from the heater core. This is were I am stuck, I dont know where to go from this point. Any help would be greatly appreciated. Jerry

Hello Jerry,

Kenny Z here,I hope I can help you out.

It sounds like you are on the right track.Just so you know the compressor normally runs in the defrost and floor/defrost positions.It should be off in the floor position.I am assuming this is the mode where it is staying on.To save time I will also assume it has automatic climate control and will give you some self tests you can do on the control head.If it has manual climate control let me know and we can proceed down that path.The system should still be able to blow hot air even with the compressor running.Take a look at this and also verify it is on in the floor mode and let me know what you come up with.It sounds like you might have a blend door issue.


Electronic Automatic Temperature Control Module Self-Test

  • The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A scan tool must be used to retrieve these concerns.
  • The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4° and 32°C (40° and 90°F) when performing the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
  • The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.
  • To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
  • If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
  • If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
  • To exit self-test and retain all intermittent DTCs, push the blue (cooler temperature) button. The control will exit self-test, retain all intermittent DTCs and then turn OFF (display blank).
  • To exit self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared.
  • Always exit the self-test before powering the system down (system turned OFF).
  • Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.




Customer: replied 8 years ago.
Hey thanks for the reply. I am pretty sure that it is a manual control unit So any additional help will be great. I did a check on my Dodge and yep, you were right, the A/c compressor does stay on when the heater is on defrost. Thats something I learned today. On the Ford, when the heater is on the floor the A/C compressor still runs and the lines do get extremely cold. My neighbor talked to the local Ford dealership before asking me to check it out. They said it was probably the heater core and quoted him about 1000.00. We know it isnt the heater core so if we can get this thing figured out Im sure he will be very happy. So your thinking one of the doors that control the airflow is not functioning correctly. Just let me know what to do next. Thanks Jerry


If the compressor won't shut off in floor mode,lets address that first.We know there is a problem there for sure and it might cure the no heat problem or lead us to it.Ok, so it has a manual climate control system.Take a look at this diagram, access the control so you can get to the wiring on the back of the mode switch.check for power on the violet wire in the floor can see in the diagram which modes let current flow on the violet wire and which do not.panel,off and floor should have no power on the violet wire.Let me know what you find.



Customer: replied 8 years ago.
Hey thanks again for the quick reply. I dont have a repair manual for the truck so I may need to go get one if I cant figure out how to get the dash apart to get to the contro unit. If so I will get back with you later today with the results of the test you suggested. Also, I definitely want to accept you help so you will get paid. Should I wait until we are done, or can I accept now and still be able to receive further help from you.Thanks Jerry


You can accept anytime,you might want to wait to see how involved we get and you can adjust the price if you feel 15 is not enough for the amount of time spent to find the problem on my end.The question remains open after accepting and we can still post on this same blog.Heres the instructions to remove the control head.No need to buy a manual,I will get you what you need as we move along.



Customer: replied 8 years ago.
Thanks for the diagram and instructions, im sure my neighbor will appreciate not having to buy a book. Update. I went out to the truck to do the tests you mentioned, but noticed that the A/C compressor is now working like it should. It is kicking in and out as it should depending on the placement of the fucntion switch. No clue whats going on there. But, it didnt seem to have much of an effect on how much heat is put out. The heater is still putting out much cooler air than needed. So should I go ahead with the tests you recommended or is there something else I should try. Thanks again for all of the help so far. Jerry


Are both the heater hoses hot to the touch?? I know you said the outlet is slightly cooler which is OK I just want to know if the hoses at the core are nice and hot.

Customer: replied 8 years ago.

This is a hard question to answer because of the subjectivity.

Ok so I went out and let the ford run and also let my dodge run until both were warm. My dodge is newer (2004) and when I touch both hoses they are almost the same temp, very hot. I couldnt leave my hand on them for but a second. On the ford they are cooler. I can leave my hand on the inlet hose for 5-10 seconds. the outlet hose is warm but cooler. On the outlet hose while my hand gets hot, I could probably leave it on it without getting burned.

On the ford both hoses are close in temp but neither are as hot as on my dodge.

Also I forgot to mention The expedition has the vents in the back passenger area with its own controls also so I think the truck has 2 heater cores, not sure. But the air coming our of the back vents is not hot either.

So what do you think.


With the engine fully warmed up the inlet hose should be too hot to hold on to for more then a second or two.At this point we need to get accurate coolant temp readings either with an infrared thermometer or with a scan tool that can monitor data steam pid information for the coolant temp sensor. The guage is not accurate enough to know the actual temperature of the coolant.In your first post you said the thermostat is operating properly.How did you arrive at that conclusion?

Customer: replied 8 years ago.

Thats how my dodge is, i couldnt hold onto it at all, but the ford is cooler and I can hold on to it.

For the thermostat, I started the car when it was cold and monitored the top radiator hose for heat and water flow by touch. I didnt feel any water release into the top hose until the car temp gauge was at normal operating temp. Now I am guessing at what normal temp is for this vehicle. My neighbor didnt really know where the temp gauge should read. Right now it is reading a constant half way between cold and hot. But I have no idea what the actuall temp is. When I looked in the reserve coolant tank the coolant is very dark, almost black looking, it probably has never been changed. I dont know if this could be contributing to the problem or not.


For the coolant temp reading. I dont have a scangauge or an infrared themometer. What are my options on this, I may be able to find a cooking thermometer that I could try to use, how should I procede.


We need to find what the temp is,,, somehow. That is the next logical step and we can't really proceed until we have that info.If the thermostat is not closing enough it will still initially warm the upper hose after it opens and act very normal.Many times when they stick the temp will be 150 - 170 and all will appear normal including the guage.But not hot enough for sufficient heat output from the core.It sounds like it could use a flush,but having the temp info is crucial at this point.Maybe you can run it by a shop and they will hook up thier scanner for cheap to see the temp??

Customer: replied 8 years ago.

Ok, so I found an infrared thermometer down at mieneke that they use to check cat converters so I assume it is pretty accurate. I took temps in 3 places for you by pointing the laser at the hoses from about 1 foot away from the hose.

142 Top radiator hose

140 Inlet heater hose at the firewall

127 outlet heater hose at the firewall

I found out from Autozone that the thermostat should be a 195.

This looks like the problem to me but I wasnt sure how much the hoses would vary the readings. What do you think?

Thanks again Jerry


Replace the thermostat and flush the coolant and you should be good to go....that is way to cold of a reading even reading the hoses.

Take care,


Customer: replied 8 years ago.

I really appreciate your help. I would never have thought that it was the thermostat because the engine was showing warm on the gauge. But comparing the hoses to my dodge they are not near as hot.

I need to talk to my neigbor, but I am going to try and get her to give you a bonus. Should If I accept your help now for the 15, will I be able to come back later and give you a bonus if she says it is ok, or should I still wait until I talk to her and then do it all at once.

Thanks Jerry

I would go ahead and wait, the question will stay open for 24 hours without activity.

Thanks again,


Kenny Z. and 2 other Ford Specialists are ready to help you
Customer: replied 8 years ago.

Thanks again Ken, I flushed out the radiator and replaced the thermostat and its good to go. The heat coming out of the vents is about 120 degrees so my neighbor is really happy. Thanks again for all of your help


Customer: replied 8 years ago.

Hey, just accepted your offer and added a 15.00 bonus, but when I received an email from justanswer it showed the payment amount as only 15.00 instead of 30.00. I thought that it would automatically charge me 15.00 plus the 15 bonus. Let me know how much you get of you dont mind.

Thanks Jerry


The $30 showed up. Thanks for your generosity!


Customer: replied 8 years ago.

Ken, My neighbor came back to me and the truck is still not getting hot enough. I checked it the other noght when the temp was about 50 and the heat is way to cool. I looked at it today and still the temp coming out of the vents is 107 at its hottest. So I took the truck down to midas and used their infrared thermometer again. With the truck fully warmed up and the heat on high the temps were as follows:

inlet heater hose:148

outlet heater hose: 129

top radiator hose: 126

These numbers are about the same as before I changed the thermostat. I am at a loss. I would be happy to pay another 15.00 for your time if you have any suggestions.

Thanks Jerry

What brand stat did you put in it?

The cooling system might need to be drained and filled with an airlift, it might have an air pocket, especially if it warms up when you rev it up.

The fan clutch is not siezed is it?

Was it ok for a while after you replaced it?

Do the temp testing on metal components like the radiator,cylinder head or thermostat housing..not the rubber

Did you flush it good also?

Customer: replied 8 years ago.

The stat is a duralast 195 degrees


After I first replaced the stat I was getting hotter air, but I did have to rev the engine up to about 2500 to get the hotter air.


I dont think the fan clutch is siezed. I can hear and see it kicking in and out.


Not sure if it was ok or not after I fixed. I though it was, but the day I changed the thermostat it was about 75 degrees. When I reved the engine to about 2500 the air was hotter than before I fixed it.


The hoses are a little warmer feeling than before I changed the thermostat, but not near as hot as my dodge.


I think I flushed it really good, I used the prestone flush chemical and flushed it out until only clear water cam out of the radiator drain. It took me probably 2 to 3 hours to get it completely flushed out.


What do you think?


Wow something sure isn't making sense.Will your infrared get right on the heater core tubes and get a measurement from there and also one from the radiator and t-stat housing?
Customer: replied 8 years ago.

It will probably be tomorrow before I can Get the temp readings you asked for. I did take out the thermostat. I put it in a pan of water on my stove and brought it to a biol monitoring the temp with a digital cooking thermomether. It did not open until right at 195. So if this is an accurate way to check the thermostat it is working properly. What do you think? Also is there anything else I can check tonight before I get you those temp readings you asked for?



I have not run into anything else on these,If the stat closes there is not much left other than air pockets,stat installed backwards, or fan clutch fully engaged all the time.

Customer: replied 8 years ago.

Any chance it could be the heater core?


Maybe the valves under the dash that direct the flow of water and air(I really dont know how this part of the system works so I am grasping at straws here).


If it does have an air pocket in the system how do you fix that?




If the engine temp is hot enough then I would flow test the core.Water flow in the core is continuous.Air flow could be a factor,but I would not go there until we know there is HOT coolant thru the core.

Air pockets are removed by draining the system and vacuuming it with the air lift tool. It puts the system into a deep vacuum and the coolant is drawn in under vacuum.


check it out here

Customer: replied 8 years ago.

Ken, so I got the heater hoses off the core and started flushing it with my water hose. I am getting intermittent flow. It flows real slow, just more than a dribble, and then I get a burst of water (with what looks like rust flakes) coming out, and then back to a dribble. I have flushed it for about thirty minutes and it seems to be getting a little better.


There should be a continous flow of water right?


If I keep at it, is there a chance that I will be able to get it cleaned out enough to work properly?


I also bought a book and read about changing the heater core if it comes to that. In the book it states that you have to get the A/C system drained and unhook the evaporator lines at the firewall in order to remove the heater core. Is that correct? I cant understand why you would have to unhook A/C lines just to replace the heater core.


Thanks as always, Jerry


Maybe you could fill the core with flush agent and let it soak overnight and then continue trying to flush it.There should be a steady flow.

You don't have to open the a/c.Here is the ford procedures.