Ford Focus no heat question

Yes, I know this is not a auto forum. Just hoped I might get lucky and find an answer quick.

My daughter just showed up with her 2001 Ford Focus ZX3 with no heat. Blower just blows cold air. Engine is warm as it should be.

My problem is . . . I don't have a clue how this thing works. Some cars shut off actual coolant flow, and some play with air blending doors.

This Focus has what feels like an electric switch, i.e. a variable resistor for heat control. So, I assume something somewhere is controlled by an electric signal. I'd like to do a fast, temp fix if possible. I opened the hood and see nothing that would control coolant flow. No remote-controlled gate valve in any heater hose.

Anybody got a clue how this thing is supposed to work? I'd like to know before I start tearing apart the dashboard.

My wife drives an 01 Focus wagon. The one and only time she had an issue with no heat, it was low on coolant. Yea I know, seems to simple. The reservoir on the passenger side has a couple of lines for hot full and cold full. I discovered the thermostat housing that bolts the engine was leaking when she would shut if off (sudden temp change and instant lack of flow). She never mentioned seeing water under it but I had in the past but just ignored it.
Also there is a sensor that screws into the block that is the temp sensor, but I don't recall what all it controls. It's located behind the alternator which has to be removed to get to it. The alternator died and had to be replaced last year so I replaced that switch while it was out. Alt swap takes several hours, some bloody scrapes and a whole new list of words to complete.
I found a lot of help from a group of Focus folks (they are more into hot rod stuff, but will help anyway) here:
Ford Focus Help

As previously posted, first check the coolant level.
Is the top radiator hose hot? If not, probably the thermostat.
With the engine hot, grab both heater hoses. If the one closest to the engine is hot and the other is not, it"s not flowing. If they are both hot, you have a blend door problem.

Could very well have a broken blend door and the heater core is simply shut off to the entire heating system. In fact she may be even getting air conditioning as well as no heat! The auto companies use a cheap plastic door with a hexagon drive at the bottom and sometimes it crumbles there and the door just flaps shut on its hinges. It has a variable control hooked into the bottom of the hex. That is what you are controlling from the control on the dash. You may be able to see the controller at the bottom of the dash by where your feet go up under by the passenger side. If you can get at the controller and take it out you may be able to reach up in there and open the door by hand and wedge it back open temporarily until you can take the dash out. And taking the dash out on that car is probably no fun. I had to do it on my lincoln Navigator and it was a royal pain for a $27 dollar part. Ford dealer wanted about $1000 bucks to do it. No kidding. I also just got to have the pleasure of doing the heater core on my Dodge quad cab pickup. If you look a the picture they were taken in the same spot in front of my pole barn. Both were hidious jobs. I think the dashes on new vehicles are the worst design of anything being made now.

Thanks, seems you hit the nail on the head. I know the heater hoses are hot. I just had no idea what actually controls the heater function. I went down to my friend's repair shop and used his on-line Mitchel repair database. He pays $200 per month for it. It showed me that the Focus does not have an electric control like I first thought. The rotary knob works on a cam that controls a cable to the blend door.

So, this is clearly a blend-door problem. I just have to find a way to force it into "heat" position and leave it, for now. That so we can get our own car back that she's borrowing today.

Davpal is going in the right direction. They use an electronic actuator to move the blend air door. You need to find the actuator and then move the temp knob and see if there is any movement. It's not impossible for the plastic door to break, but a failed actuator is much more likely.

Got the car in my shop. Ran it awhile and found one heater hose totally cold. Blend door was working fine and coolant system was full. Temp gauge read right in the middle where it should be. So, obviously no flow, but why? In front, on top of the radiator is a plastic water manifold with three water connections. One end goes to the lower radiator hose. The other end has two hoses - one to the heater core and one to the engine block below the thermosat. All hoses were hot except the one to the heater core. So, I pulled the hoses off to see if there was any sort of blockage in that plastic manifold. Nope. It was clean. So, I put all back together and now? The heat works fine. Now I'm really perplexed. I fixed nothing. Seems maybe I might have purged some air out a hose when I removed?

Whatever the problem was, I'm sure it will happen again because I don't think I fixed anything. That water manifold was broken off it's mount and hanging down a couple of inches low. I remounted it on top where it should be, but I can't figure how that can make any difference.