Heating Issue

[TMD]

When the colder weather hit we switched the temperature gauge to heat, and our unit continued to blow cold air. I am no mechanic, but I have read through this site enough to know what to include on this post to get the most accurate answer from the real mechanics on here.

Our truck is a '05 Sport Trac XLS with 60,000 miles on it.

With the truck on, I'll turn on the A/C unit and the system blows cold. I can drop the fan speed and the system cooperates. I can switch between all exit points for the airflow with normal results. It is only when I turn the temperature gauge that there is a problem. Instead of turning over to heat, it remains cold.

Our coolant reservoir is where it should be. The truck reaches normal operating temperature within the first few miles and doesn't show that it's overheating. The higher radiator hose is warm to the touch after driving a few miles as well, with both hoses in good condition.

I checked all of the fuses where I could see the inside to verify for a break, with all still operating fine. The larger one's without a view could not be verified visually and without knowing how to check them, and without any schematic, they've gone unchecked.

I'm hoping that covers it all. Every bit of help would be appreciated, as I can not afford to run it to a garage and will need to do this repair on my own.

I'll be on this site indefinitely if anyone has any further questions.

Thanks for the time.

 

[BrooklynBay]

Welcome to this forum! The first thing to do is to see if both heater core hoses are hot. The heater control valve could be bad or the heater core could be clogged. Another common problem is the blend door. They tend to get stuck in a certain position.

 

[TMD]

Thanks BrooklynBay!

I'll take a look.

 

[TMD]

Both heater core hoses run hot. Does that point me in the direction of all three problems, or would one or two be eliminated?

Thank you in advance.

 

[BrooklynBay]

Since both heater hoses are hot, this would eliminate the possibility of a clogged heater core or a bad heater control valve. Check the blend door next.

 

[garveyb]

Not sure if it will apply BUT mine was doing the same thing. I backed the temp off a bit and it worked fine. I am guessing the contacts inside the control need replaced or cleaned but this works for the minute for me.

Hope this helps

 

[Dracus]

I have the same problem with my 99 XLT 3.0. Could you tell me where to look for the BLEND door?


Dracus

 

[BrooklynBay]

Welcome to this forum! Check # 36 & # 61 in my list of useful threads for more information.

 

[Dracus]

Thank You Brooklyn

 

[diego]

Do 3rd gens have blend doors like the 2nd gens?? But the blend door wpould probably the first thing id look at, seems to be a big problem on explorers along with the door end rod clips and everything else made of plastic. I just cut a hole in my heater core..(not recommended) but when winter comes I open my blend door and in summer I just pop the hole back open and close the blend door. If this is your problem Ive seen treads on replacing it and also going the route I did and cutting into it.