Hello all, just became a member today to this great site, lots of great information. It is getting cold in Wisconsin and my truck does not want to heat up. I did the obvious first and replaced the thermostat and that did not help. I believe the heater core is plugged. I felt the hose leading in to the core and it was warm the one returning was cold. Will I be able to "blow" core out with air or water by isolating the two hoses (in and out) and applying water or air? Any help is appreciated.

 

the heater core being plugged sounds unlikely unless you poured a bunch of powdered stop leak in the cooling system for some reason. If your floor's wet, the heater core is leaking. You might check the center temperature ****. For some reason they are prone to cracking and won't turn controller from cold to hot. Ive seen a few trucks with this problem.

 

I did not put in any stop leak. I was able to disconnect the hoses to the heater core and flush it out. I noticed a little heat through the panel setting but no heat when i set the control to floor or defrost.

 

Did you check for adequate water flow through the core while you had the flush setup going?

 

the water flowed freely, there wasnt any blockage. It sounds like the dampers are working. When i change to different settings I can here them moving.

 

I'm having the same symptoms as you but I'm looking for the Heater control valve. Coolant is not being allowed to flow through the return line in the engine compartment. I just need to find the control unit that controls the flow. I'm leaning towards the control unit under the radio right now just as
mbmnascartrk98 staited earlier. I found a small insert on page 3-24 of the Haynes manual, under heating systems. It points to the control unit but doesn't say where it's located, if flushing does not solve your issue. That's where I'm at! Locating the lost control unit???

 

took it in to a shop to get a better flush of the heater core, (all my outside hose are frozen due to cold weather) It seem to heat up a little better but I am used to the blazing heat most Ford heaters put out. Please let me know where and if you find that control unit.