I have a slight problem with my '02 Mondeo TDCi Ghia X, when the aircon or climate are switched on and I am sitting in traffic or travelling slowly I can hear a cooling fan come on for a second and then switch off again, on again, off again etc etc, although the aircon etc seems to work OK the fans never previously did this, the dealer diagnosed low gas pressure though topping up did not cure it, they are now saying it is the "low speed fan" that is cutting in and out though the "high speed fan" is ok, they need to have the car back in to run diagnostics to determine the cause, anyone have any ideas?
Also can anyone advise as to under what conditions these respective fans are supoosed to opperate?
Many thanks.
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Hi, my fan seems to come on as soon as the AC is switched on and it says on until the AC is off(i think).
Did they do a pressure or leak test before topping up? It sounds like you have a leak. Do you use your AC all year round? Is it ice cold when on full fan speed at min temp?
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With the a/c switched on ,Both cooling fans run at slow speed up to a road speed of approx 60 kph.(controlled thro engine management system).fast cooling fans only come on during high ambient or engine temps.
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Yes the aircon is icy though have not tried it a 30 degC for 9 months or so.
I know what you mean re the slower fans, sounds to me as though it is a fast fan switching on for a second or so then off again, on again, off again, any ideas as to the cause of this? Could it be connected with an ambient or engine temp sensor?
Many thanks.
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Have a proper look and let us know whats actually happening. ie. are both fans running low speed all the time? Is it the high speed fan coming on and off, or one of the low speed ones?
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Hello All, I will try to do what Dave N suggests tomorrow, Sunday, and post again.
Thanks.
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Hello All,
I have not had a chance to have a close look myself however it is apparent that it is a high speed fan going on and off very regularly, the dealer has advised that it is doing this to compensate for the fact that the (or a) slow speed fan is not working, this, they say, is due to a "burnt out multi plug on the back of the low speed fan resistor".
Where is the multiplug/resistor situated?
What is involved in making a repair, I assume a new resistor?
How many relevant fans are there? I assume one slow speed and one high speed?
Many thanks.
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Sounds about right. This used to happen on the 5 series fans. Usually the resister is on one of the fan supports, but trace the wiring back a bit till you find it. I suspect ford have a fix for this that involves a new bit of wiring and plug.
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The slow speed fan resistor is situated in the plastic fan cowling,just below and to the left of the l/h fan motor .(nearest battery).If you follow wiring down from motor ,you will see a large 2-pin rectangular connector with 2 fat green wires attached.Failure of this resistor will cause the fan/s to cycle on high speed mode.
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Hi Doc,
Following your description I can see the connector to the resistor with the two thick green wires leading into the loom though the resistor must be hidden in the housing?
The dealer said that the connector is burnt out though externally it looks fine to me. However if it is burnt out I guess it will need to be spliced into the loom?
Seems that it is most likely that the resistor or perhaps the pins on the resistor are burnt out, any thoughts?
Do you think it is just a matter of the resistor failing or could there be an underlying cause?
Lastly is simply replacing the resistor likely to effect a cure?
Many thanks, advice much appreciated.
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I would think it is just the resistor that has failed.It is a fairly cheap & cheerfull wire wound unit that costs about £25.Undo the 2 screws that secure it to the plastic frame & look at coiled wire;you might be lucky & find a crimped connection adrift.Think you have to take out complete fan & motor housing cos it is fixed from inside.
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Hi Doc,
Many thanks, I will look further in to it.
Regards.
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Hello All,
The aircon is working OK (albeit with the high speed fan going on and off to compensate for the fact that the slow speed fan is not working) therfore I have not rushed to get the car back to the dealer on this. However I had a close look myself this morning, it is apparent that the plug on the back of the resistor is badly burnt out though the pins on the resistor look ok.
I guess the plug has burnt due a short caused by moisture, do you think that the resistor will be also be damaged?
Is there a test I can conduct, perhaps measuring resistance across the pins?
Many thanks.
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Calling elekie & a/c doctor and Dave N ?
Regards.
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Sure, measure the resistance. Don't know what it should be, but it should be obvious if it's open circuit or shorted. Might be worth finding a mondeo website, where you'll probably find someone else has already come across it.
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If the plug connector is burnt,you could cut it off & crimp on 2 large spade connectors & try that.Worst way it will not work which is the condition you have now.The resistor value is very low,probably 1 ohm or less.
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Hello Both,
Many thanks for the advice, I had thought of the spade connectors idea, perhaps insulated with some silicone, if it still does not work then changing the resitor will, I guess, be the next step. On the otherhand, I might leave it to the dealer, they owe me one, they suggested that low gas pressure would cause the fan to cycle, they charged for an aircon service which made no difference, then on further investigation (a quick look under the bonnet!) found the burnt plug.
Regards.
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Well the dealer seems to have done a good job splicing on new spade connectors and buiding them into the old plug, all seems well. The menu fix for this problem is a new section of wiring loom, expensive in parts and labour.
Regards.
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Update, replacing the plug with spade connectors did not solve the high speed fan cycling problem however I have now changed the resistor myself at a cost of £25 and all seems fine.
Regards.
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