Interior Heater problem

[Logiz5500]

Hi everyone,

As I am just new to this forum I shall try to be as informative as I can in describing the problem:

Me and my buddy (Dutch) have started travelling in Australia (backpacking) and bought ourselves a Ford Explorer 1998 XLT 4.0 SOHC as we wanted to do some off-roading on our travels. (Note that we hardly have tools around on our travels.)
Car history: We have receipts saying the car has had a brand new engine in 2007. We replaced leads, fuel/air/oil filter, eng oil, spark plugs and lower ball joints 5 months ago.

The days have started to be shorter and a lot colder here in south Australia than the warm north. We wanted to heat interior and found out it won't work.

The switches on the heater panel work, as (cold) air will blow from the vents that we set it to (also AC and Max AC works). The amount of air can be set as well. However, the heater switch does not make a change and the AC pump will always be activated independant of which vents we set it to.
After popping the hood, we found out that the tubes (carrying coolant) leading towards heater housing (inside the car) won't warm up as well.

We went to a pick-a-part shop and replaced our heater panel, this did not do the job and gave trouble with vents..

The engine warms up, but stays cool as it should be. So would this mean the thermostat is allright or should it be replaced?
Anyone having same trouble have a solution?

Thanks in advance!

 

[Blee1099]

I suspect the heater control valve.. Looks like this

Have a buddy look under the hood when the heat is turned on, there is a lever that should move when you turn on the heat.

 

[Logiz5500]

Will do that within an hour.
Can I find that near the thermostat?


Edit:
Took a look, can't find anything like it, there doesn't seem to be anything moving either.

 

[ludasisk]

Check thermostat could be stuck open