batsona

What sensor determines when the radiator fans come on? When it goes bad, does it keep the fans coming on more than they should?

My radiator fans run more often then they used to. In the fall & winter, they nearly never ran; they would only run if I turned on the A/C compressor.

My cooling system is good -- no leaks, pressure OK, heat works OK, temperature gauge is unchanged from the way it normally works. Everything about the car works OK, and nothing has changed recently; it's just like something is telling the fans to come on too often.

Any ideas? Thanks!

R.S.LOGAN

You will have to supply more info , i.e year of car , what engine would help .

R.S.LOGAN

Could check the cooling fans resistor , usually at rad between the fans on some models .

batsona

Sorry.. OP here.. 2001 FOcus ZX5 auto-trans. 2.0 Zetec 4cyl. I'll check the state of that resistor in the morning, when there's more light.

R.S.LOGAN

Found this which shows what I mean , might help you .

my 2003 ford focus over heats when i turn the heater on - JustAnswer

djzx3

The resistor would be your best bet, on your model it is at the top, right between the fans. It should look like this. This is a Duratec though, it is on the bottom on the Duratec.


Before you take it out, unplug it and test it for continuity, sometimes it breaks connection all together, like mine have.

Some other things you should know too is; the resistors on the Zetec and Duratec, and even the SPI are all the same, so don't waste $60 buck at the dealer, go to a junk yard and pull like 6 of them from any focus.

Also to get it out you will have to move the whole fan assembly up and forward, Very simple just be careful not to man handle anything.

But you should find a clip on each side of the fan assembly.

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~---------------~
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If this^ is both fans, the wavy lines symbolize where the clips are, and they are just pull up, and move forward.

__________________
2000 focus wagon 2.0l DOHC Zetec
04 Subaru WRX,:)



How-to directory.

Ford focus DTC codes.

Ford= First on race day.

batsona

Thanks for all this - I'll do those electrical tests mentioned in the artical.

R.S.LOGAN

Glad to help , the tests should enable you to locate the problem .Let's know how you get on or if you need further help / advice .

batsona

OP here: OK, from doing more reading another site, it appears that the 2.0 Zetec has two types of sensors dealing with temperature detection. Does this mesh with what the experts here see? I guess I need to understand what-sensors-do-what, so I know what I'm dealing with.

a.)Cyl head sensor... near the top edge of the block, right beside where the intake manifold bolts on. It senses the temp of the block itself rather than the coolant, because if your water pump breaks, and coolant stops flowing, the temperature of the Aluminum is key.

b.)Coolant temperature sensor... This is a 3" long fat pin that screws into the block near the alternator. It has a wire dongle that connects to the wiring harness.

The first part of my VIN is 3FAHP37372R.

Bert

The one for the fan is next to the alternator.

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Bert