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Hi, I am having a problem with my cooling fan not running, so far i have tested the fan by connecting it to the battery and there is nothing wrong with the fan, i strongly suspect it has something to do with the thin blue wire coming out of the cooling fan control unit that is located on the fan(control unit is working), i have found that this wire goes from there to the big center connector in the fuse box but from there i have not been able to locate it. I also found the the fan control unit needs the blue wire do connect to ground in order for the power to go trough to the motor.

I have searched for all sorts of diagrams and i do not find anything, could this be a problem with some temperature sensor or is it more likely that it is a problem with the cars computer system, PCM (Powertrain Control Module) or ECU ?

I´ll leave some pictures

Thanks
 

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2006 ZX5 2.0, 2004 ZX3 SVT EE. 2004 ZX3 SVT
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The cylinder head temperature sensor is the black wire in the middle of the valve cover. Pull the rubber boot back and disconnect and check for corrosion. There are 3 things you have to have. A good fuse, a good relay, a good temp sensor. All are very cheap.
 

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2004 Focus Wagon, Zetec DOHC, Auto
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The cylinder head temperature sensor is the black wire in the middle of the valve cover. Pull the rubber boot back and disconnect and check for corrosion. There are 3 things you have to have. A good fuse, a good relay, a good temp sensor. All are very cheap.
I don't think the CHT wire colors are the same on an '07, and no relays are used as the control module is solid state. The blue wire is a variable voltage signal from the PCM to control the fan speed. The CHT can be disconnected and tested to see if resistance is close to being normal. Ford Focus Cylinder Head Temperature Sensor?

To OP... Do the fans come on with A/C?
 

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2006 ZX5 2.0, 2004 ZX3 SVT EE. 2004 ZX3 SVT
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I don't think the CHT wire colors are the same on an '07, and no relays are used as the control module is solid state. The blue wire is a variable voltage signal from the PCM to control the fan speed. The CHT can be disconnected and tested to see if resistance is close to being normal. Ford Focus Cylinder Head Temperature Sensor?

To OP... Do the fans come on with A/C?
This site shows relays for the cooling fans for 05-07. What am I missing? Ford Focus (1998 - 2007) – fuse box diagram - Auto Genius
 

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Likely. Don't you just love it when they unitize that stuff to be bought in entire major subassemblies? The 'relay' is the cooling fan module there.

I replaced a module once on Tempo with a simple relay and it worked for years but likely by now the PCM control there for variable fanspeed is CAN or duty cycle and not easily replaced as a control method, and why they use it, it forces expensive parts buying.
 

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Ok. fan works by testing it with a direct 12V connection.
But how did you test the fan control unit?

Also, you just could try getting a new fan control unit & seeing if all works like it should.
If a new fan control don’t fix it, you can return it.
No money lost & one step closer to diagnosing the issue.
 

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I'd be sure of return policy before doing that, ours used to change every minute. We would accept back even broken parts until they forbade us taking any electrical back at all once installed, then it would flip over and begin again. The seller taking parts back is never a given. When the parts talk to each other like CAN then it gets even worse, common for one part to screw up others then all returns are junk.

A wide open return policy with no restrictions on it is the biggest reason you get bad parts in new boxes. Or missing parts when people keep them on purpose. And why the parts shelves look so ratty now, none of the boxes are virgin any longer. America thinks you simply change new parts until you get the one that works.
 
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