i only relpaced speed 1. would it not work if the second speed relay is bad to? or could it be some bad sensor somewere? the fans wont turn on even if i turn the ac on full blast
cooling fans will only kick on if i jump the relay, replaced the relay and still nothing even at 102C..
yamaha940
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Ok so you have verified that the fans work so you know the electrical path from battery to fans is fine. So it must be something to do with the signal path from the computer or from a sensor to the computer.
I would start by finding the water temp sensor. It is what is called a negative coefficient thermistor. Basically as the water temperature goes up the resistance across this sensor goes down. Without getting into all the electrical garbage describing what voltages you should see out of the sensor and when (it gets complicated) you should be able to use an Ohm-meter to measure the resistance across the temp sensor when the engine is cold and then warmed up. Just unplug it and while the engine is cold you should get a very high Ohm reading. Some cars have as high as 10000 ohms of resistance. But keep the meter on the sensor as the car warms up and that reading should go down by quite a lot. If the sensor is working properly, by the time the car is warm the resistance reading across that sensor should have gone down by quite a bit. I don't know what it would be on the Focus.
If you want to know more confusing things about this, here is a good article. Just scroll down to where they start talking about thermistors because that is where it applies to this.
http://www.asashop.org/autoinc/may98/techtotech.htm
I would start by finding the water temp sensor. It is what is called a negative coefficient thermistor. Basically as the water temperature goes up the resistance across this sensor goes down. Without getting into all the electrical garbage describing what voltages you should see out of the sensor and when (it gets complicated) you should be able to use an Ohm-meter to measure the resistance across the temp sensor when the engine is cold and then warmed up. Just unplug it and while the engine is cold you should get a very high Ohm reading. Some cars have as high as 10000 ohms of resistance. But keep the meter on the sensor as the car warms up and that reading should go down by quite a lot. If the sensor is working properly, by the time the car is warm the resistance reading across that sensor should have gone down by quite a bit. I don't know what it would be on the Focus.
If you want to know more confusing things about this, here is a good article. Just scroll down to where they start talking about thermistors because that is where it applies to this.
http://www.asashop.org/autoinc/may98/techtotech.htm
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Oh and I should mention that on the Zetec its not actually a coolant temp sensor. Its a cylinder head temperature sensor. It works the same way and for the same purpose but you won't have water flowing out of the hole if you remove it for whatever reason. And it should be located on the side of the cylinder head. I believe the transmission side.
ok thanks 
i'll check that out.. but what still puzles me is no mater what. the ac will not turn the fans on. and i herd that as soon as you turn the ac on, the fans should kick on full speed no mater what the engine temp is. and mine is not.
i'll check that out.. but what still puzles me is no mater what. the ac will not turn the fans on. and i herd that as soon as you turn the ac on, the fans should kick on full speed no mater what the engine temp is. and mine is not.
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It very well should and its very likely the temp sensor is fine. Just covering all the bases first. It could be the cooling and AC fan problems are two different problems entirely. If the AC system is damage in some way the fans will never get the ok to turn on. But I doubt it cause it sounds like the AC works or worked before all this.
well i never realy used the ac cause it just blew heat.. but when i replaced my radiator and shroud, i took the ac thingy off too so i have no more freon in it... whould that cause a different cencore in the ac to not send the signal?
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102C is 215.6F
The thermostat in your car is probably 92C or 197.6F
My fans don't come on until 107C or 224.6F which I'm assuming is the low speed fans. I've never seen anything in FORD's literature where the TEMPERATURE is stated when the fans come on at LOW SPEED and HIGH SPEED.
It's been awhile but..... if you pull the electrical connector off the fan assembly RESISTOR the fans appear to go into HIGH SPEED mode (might be a fail safe mode). I read somewhere when someone else did this they thought the fans went into the LOW SPEED mode after a few seconds, then after a few seconds more they went into the HIGH SPEED mode. Replace the connector and they shut off.
The thermostat in your car is probably 92C or 197.6F
My fans don't come on until 107C or 224.6F which I'm assuming is the low speed fans. I've never seen anything in FORD's literature where the TEMPERATURE is stated when the fans come on at LOW SPEED and HIGH SPEED.
It's been awhile but..... if you pull the electrical connector off the fan assembly RESISTOR the fans appear to go into HIGH SPEED mode (might be a fail safe mode). I read somewhere when someone else did this they thought the fans went into the LOW SPEED mode after a few seconds, then after a few seconds more they went into the HIGH SPEED mode. Replace the connector and they shut off.
Without any freon in the system, the high/low pressure switch in the A/C line will prevent the unit from working. That would not have a demand for the fan then. Just thinking of some other things here....
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Well the fans won't operate because the AC system isn't "working" so to say, properly. So the fans while AC is on theory is out.
That still doesn't explain why they won't come on at all while its warming up. Since your temperature gauge is reading a temp I am assuming the water temp sensor is also working. I believe it is like a_2000_se says. The car just isn't "warm" enough for the fans to come on.
Try this. Let the car warm up normally and then go to the throttle body and hold it open to about 2000-2500 RPM for about 2-3 minutes. This should force the cooling fans to come on because if they don't, the car will start to overheat. You can do this inside the car I guess. Just hold your foot on the gas like described above for the alotted time. If the temp gauge starts going towards the red the fans should come on or even come on before that.
yeah i tryed that.. and when i held it at like 3000rpm, the temp actualy droped from 102 to like 98. im getting my plate transfered tomarow cause it should be ok to drive as long as im moveing and watching the temp closly. i drive the highway to work anywho. and so what your saying cince my ac has like no freon in it, the fans wont get the signal to work then?
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The fans should work BUT they won't get the signal from the 'AC circuit' to work when the AC is on because it has been disabled (no pressure from the freon on the AC pressure switch).
The fans should still be turning on when the temperature set points are reached. You didn't mention if the fans were on when your temperature dropped from 102 to 98. Even if they WERE ON that isn't really much of a temperature drop - should be more like 15C drop.
It almost sounds like you have restricted flow in your cooling system - if the fans are coming on. It isn't that hot yet in PA is it?
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^^ Sure - but we were attempting to see if he just wasn't reaching the temperature set point for the fans by fast idling the engine.
I would think that at 3000rpm you would only see a temperature rise if the fans weren't working. He saw a decrease - with no airflow? Hence my question about the fans - still not much of a drop in temp.
Something doesn't sound right.
I would think that at 3000rpm you would only see a temperature rise if the fans weren't working. He saw a decrease - with no airflow? Hence my question about the fans - still not much of a drop in temp.
Something doesn't sound right.
with the digital temp guage in the car. you know when you hold your milage reset button in wile you start the car. then keep it held in until your milage thing says test then you let go and it says gauge, and the gauges sweep. them you can toggle through haveing a digital spedomiter, tack and thermomiter. thats what ive been going by
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i just replaced my resistor and plug for the resistor and mine is doing the same thing, fans don't come on until the needle moves between normal temp(needle strait up) and and hot, and it doesn't cool it down fast enough, i have to open my hood and shut the car off, i was just checking my fan relays and found that my FAN 2(R10 in fuse box) is kinda melted on one corner
![Image]()
![Image]()
is this some thing i should worry about?????
is this some thing i should worry about?????
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