Im sure this has been asked, just cant find it. My 2000 Ex has no heat, coolant is good, thermostat is good, heater control valve hoses are hot in and out, heater core outlet feels hot. If the blend door is stuck or broke can I get to it without pulling the dash and if so how? Is there a way to test the control switch on the dash to rule it out? Thanks guys. Rob

 

If your 2000 Excursion has the same in-dash components as my 01 Super Duty (probably), there's some stuff you can do to diagnose it without disassembling the dash.

1. Empty the crap out of the glovebox, then fully open the door (squeeze side tabs in) and let it hang down.

2. Behind the glovebox is a plastic cover over the heater core that's held on by a 6-10 screws. Remove the cover.

3. This will allow you to fully gauge how hot the heater core is. Be careful, it can burn you if it's at full temp. You can also get emergency heat in the cabin this way, except you won't be able to control it easily.

4. You can also, without removing the heater core cover, pop the blend door actuator off the top of the plenum and can observe it while the temperature control on the dash is turned. Last year, mine had gone intermittent and I found a cold solder joint on that board. I re-flowed the joint and the actuator is still working properly a year later.

5. With the actuator off, you can use a 1/4" drive extension dropped down into the slot where the actuator's output coupling mates with the top spindle of the door and manually move the door. This will allow you to see if it's moving normally or if it's broken.

Have fun!

 

Thanks Project, I never thought about checking the door with an extension, would the heater core cover be hot enough to tell if the core had flow or should I just take the cover off ? I was behind the glove box last night but didn't get to far into trouble shooting and saw everything was right there, thanks again!

 

This is exactly the problem that I am having and the project I am trying to fix today.
All my fluids are good, thermo is new, heater core seams very very hot.
Blend door is moving, but luke warm air coming out of the vents.
I took the plastic cover off to the heater core, turned the temp dial and it went from cool to pretty hot(much hotter than what is coming out of my vents. When I put the cover back in place, I am still getting luke warm air. I don't get it.
The rear, I am getting no heat

Makes no sense to me

 

After the blend door, doesn't the air just go straight to the vents?

 

Your blend door is not properly diverting the airflow through the heater core or the exterior of the heater core is clogged up with "stuff" so the air can't get through it.

 

Thanks Project.

Is it possible for you to kind of clarify how that works?
My original thought from the get go almost a year ago was the clogged heater core. Ive done a flush of the core and did not see bad results. Did gunk come out? Yes some, but not very much.

 

Note I said "exterior" of the heater core.

Dust, dirt, pollen, critter nests, etc. Same stuff that a cabin air filter, had one been installed, would have caught. Usually, it's the evaporator that catches this stuff.

 

Ok, well I pulled the heater core cover off and its cold, blend door works fine watched it cycle several times. Went under the hood and the inlet to the heater control valve is definitely warmer then the outlet hoses. I pulled the vacuum line of the control valve and no vacuum. Where does this line lead to and where is it so I can trace it ?

 

I see what you mean.
Directly behind the cover the core is very clean looking. The other side I am assuming could be clogged. What would be a good method of cleaning the other side without having to pull the core?
Compressed air?

Thanks for your help

Sorry Yankee, I hope I did not hijack your thread. I will help where I can

 

Yank,

That valve is supposed to open when there's no vacuum, allowing coolant flow through the core. Check to see if the valve is frozen in the closed-off position.

gerk3,

Try pulling the blower motor and see if you can see what's on the other side of the core. I'm guessing on this, I've not pulled the blower out on whatever you have.

 

OK, I will need to find where it is located.
I have a 2000 Ford Excursion

 

Project, so there will only be vacuum when the A/C is on correct? How do I check the valve, it doesn't look like you can manually operate it.

 

Only in MAX A/C - no coolant flow. All other positions, no vacuum - full coolant flow.

If there's no external actuator visible, you'd to remove it and check for valve operation manually. It's supposed to have a spring mechanism that causes it to open whenever there's no vacuum thus allowing coolant to flow through both hoses and the core.

 

Thanks project, I don't see any way to cycle the valve, but all the outlet hoses are hot, everything else has checked out so that leads me to believe the heater core is clogged. Thanks again