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So after a full hose check, rad flush and new coolant, I can get at best 'warm air' into the passenger cabin - which with -5 already and -40's around the corner is not good.

The engine is producing good heat, everything seems to be flowing as it should but none of that lovely heat is getting into the cabin.

As an aside, last winter we thought the fan speed resistor had quit as only the high speed setting would work, so we bought another one, installed it, switched it on - all 4 speed settings worked fine for the first 3 days after which - same as before only the high speed working. If the one fan speed is working - what is causing the others not to work?
 

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The blend door is operated by the temperature selector. By turning the selector back and forth, you should hear the door opening and closing. The Focus does not have a heater valve like some cars...the door is used to simply allow air to flow through the heater core or not, or partially depending on the selection.
 

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There is also an a/c bypass door that if open will do same thing, it has to be the opposite or closed to work. So, two doors there. That a/c one is exposed when the glovebox is opened then fully dropped to dump its' contents on the floor. Look at blower and the small slits in box there, the slits should have the door behind them blocking the slits from passing air, if the slits open up into deeper area the door is still open and needs shutting. The shaft to that one is known for stripping to not work, you can make a hook out of coat hanger to reach inside slot to pull door back down closed.
 

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The blower switch as well can fail to give only high speed, happened to mine.
 

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"....worked fine for the first 3 days after which - same as before only the high speed working"

Your new resistor block has probably been ruined. You can check it with an ohmmeter. See if there is continuity between pin 1 and the other three pins. If there is no continuity the thermal fuse has been blown due to the dragging fan bearings.

A schematic of the fan circuit is in this thread:
http://www.focusfanatics.com/forum/showthread.php?t=329049

Speed 4 bypasses the resistor block and will continue to work even if the block is bad.

Be sure and check for junk (leaves and other trash) behind the evaporator coil while you have the blower motor out. Ford did not put a cabin filter in at the factory...just a placeholder for one under the cowling.
 

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Discussion Starter #9
@Focusknot: Blender door working fine, air gets redirected appropriate to selector setting.
@amc49 - will check this out for sure, as it happens the ac hasn't worked since 2012 when we went to get it fix only to find 'something' wasn't available anymore so we left it empty of freon and disconnected.As to resistor blocks and speed switches not working - both being electrical makes 'em beyond me, if either is the issue - it'll have to stay that way!
 

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Blender door working fine, air gets redirected appropriate to selector setting.
That is good news! If it was not working the repair could range from very simple all the way to having to tear the entire dash apart. Now to check the A/C bypass door per AMC's post.

As to resistor blocks and speed switches not working - both being electrical makes 'em beyond me, if either is the issue - it'll have to stay that way!
I understand. Troubleshooting electrical is difficult for many. However, you could turn this into just a mechanical repair by replacing the blower fan and resistor block.

If you don't replace the fan I predict additional problems will develop with it. As the fan bearings continue to dry out and the fan struggles more and more to run, it will eventually start blowing the fuse. Hopefully it won't burn any wiring. So, either make the repairs now or expect for it to stop running in the near future.

Cheers!
 

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I got to thinking about the A/C bypass door that is described above and I think that is the recirculation/fresh air door. I am not familiar with an A/C bypass door being there. If that is the case, then your heat should still work regardless of the position of that door.

If you are only getting warm air AND the blend door is working correctly...all the way from cool to hot on temperature selector switch...then I am leaning towards a plugged heater core.

When you had the flush done, you don't mention anything other than the radiator. Was the full system flushed or just the radiator? The heater core should be back-flushed and is not too hard to do.
 

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These are full flow to the heater core all year long (again for sure on the earlies, I have '00 and '02) and why generally most of the time the core does not plug up, that is much more likely on old school cars with water control vales that cut off flow to the heater core. That is what allows them to plug when the sediments settle to stagnate and clump. Clogged core on these is pretty rare.
 

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This post contains a fairly good description of how to test for a plugged heater core and how to clear it: http://www.focusfanatics.com/forum/showpost.php?p=4900826&postcount=15

Note that he had to rev the engine after he did his work. This is because the heater core is filled with air after you have completed the flush and that air is often not pushed out by the water pump at idle conditions. Revving the engine a couple of times will burp the core.
 

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FocusKnot I owe you and others here an apology, I'm an idiot. Your surmising was correct on that a/c bypass (recirc) door not affecting heat output.

Something about what I posted (I've wiped it now to be gone) kept gnawing at the back of my mind and I went out to the car and directly checked that door action for heating effect. I was DEAD WRONG THERE. The door open or closed effects the air output only slightly and the temperature not at all. I apologize to Vision1961 if he actually worked on things under my assumptions, which apparently were that ONLY.

So where did that idea come from? Part of the digging in the cobwebs that are my brain at 60+ years old now. I know for sure I fixed an AMC Concord once closing that door when it wouldn't heat and instant heat doing so. I locked that into my head good back then and it has probably polluted more recent thinking. Like so many other things do when you assign them as firm rules only to have them shattered to pieces with the next car's design changes. Digging in the rubble there was what got me to thinking I thought I knew when I really didn't and only one cure for that. Test the idea NOW. I failed.

Again I apologize if I misled anyone incorrectly.

Looked at heater core supply path as well. When stat is open or closed the core is supplied pressure by part of the bypassing water from the small hose on back of stat housing. The suction side of it is the hose running from core all the way up to the plastic manifold at top of radiator. The other water flow either uses the small hose on front of housing to bypass radiator when stat closed or goes through stat when it is open to go to radiator. The disc on back of stat makes a clean switch between the two loops there when it closes at stat fully open. The bypass loop heats the water up faster until car is warm. The heater core itself has full flow at all times. This is on zetec engine.
 

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Not to worry AMC!

I'm old and my brain cells are dying...sometimes I can't even keep my cars straight and I only have two to work on now that the kids are gone.

And the other thing that happens to me is that what I type is NOT what is in my head! Frustrating.........
 

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Discussion Starter #16
There is also an a/c bypass door that if open will do same thing, it has to be the opposite or closed to work. So, two doors there. That a/c one is exposed when the glovebox is opened then fully dropped to dump its' contents on the floor. Look at blower and the small slits in box there, the slits should have the door behind them blocking the slits from passing air, if the slits open up into deeper area the door is still open and needs shutting. The shaft to that one is known for stripping to not work, you can make a hook out of coat hanger to reach inside slot to pull door back down closed.
@AMC - thanks for the AC bypass/blend cover tip off. Attached are photos of the temperature achieved while the vehicle was standing still (while popping out the glove box) - looks pretty good eh, next are the bypass cover itself, seen closed, it opens nicely using the recirculation switch. The AC tank and finally the temp guage after a 6km run at 80kph average - all temperature gone, not nice at -17 as it was.

So we asked a local mechanice (cowboy) to fit a new thermostat, instead he chose to flush the whole system and charging us $124.00 pronounced it all working. Several days later and it clearly wasn't so I ask him to now do the job he was originally supposed to do (NB. if I had a garage, I'd do it myself) which he finally agreed to do and even quite surprisingly offered to do it on his dime, we took it back, got the new stat fitted, the cabin temperature is all good "that'll be another $134.00 please'' and no amount of wrangling would get him to honour his words of the day before - or even meet us part way!

So we have the heat we need and he has lost a customer but... he did find someone who will never recommend his business to any other potential customers - was that really worth $134?

Anyway, lesson learned. Thanks to FocusKnow and AMC for help along the way.
 

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I'm speechless..........................and that's pretty damn rare. Maybe another condition has to be in place at same time. I thought it changed it years ago but when I did it like two days ago nothing, no change at all. I swear I'm not crazy (DON'T START!!!) LOL
 
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