FOZ500
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| posted on 31/7/08 at 12:44 PM |
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Zetec fan switch
Why am I getting a constant signal out of my fan switch? I bought a new one and that gives me the same so am i miss the plot here. I was under the
impression that as the switch warms up the contact is then made!! and luss the fan starts!!!
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r1_pete
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| posted on 31/7/08 at 12:51 PM |
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The Sierra one on my Raceline water rail is O/C untill hot then closes and completes the circuit, I'll have a look at the wiring diagrams for
the zetec when I get home....
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Paul TigerB6
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| posted on 31/7/08 at 01:08 PM |
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The fan switch will only switch on once the coolant reaches a set temperature and then go off at another set temperature. Not sure what signal you are
trying to measure but would think you should be looking for continuity once the coolant reaches the set temperature
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02GF74
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| posted on 31/7/08 at 01:12 PM |
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how are you measuing this "constant signal"
1. remove or isolate swithc from carthere should be
2. there will be one or two contacts.
3. measure resisitance between each contact and body of switch and report back. (body is usally earth contact).
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Paul TigerB6
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| posted on 31/7/08 at 02:47 PM |
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quote:
Originally posted by robocog
Thought the Zetec used 2 temp sensors on the thermostat housing that when the ECU detects a certain temperature the ECU turns the fan on ?
Temp sensors = different resistances at different temperatures
There is one at the top - this as far as I understand is the temp sensor for ECU and the one at the side (under the hose outlets) for the dash
gauge
[Edited on 31/7/08 by robocog]
The above is 100% correct as fitted to the original donor car with the top sensor feeding the original Ford ECU. As this ECU is usually junked then
the sensor isnt really suitable is it??
Dont most kits utilise a new fan switch which as Rob suggests could be a VW unit in a Polo rad / switch fitted to an adaptor etc - so long as the on /
off temps correspond resonably well to that specified in the zetec manual.
What switch are you therefore using??
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Danozeman
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| posted on 31/7/08 at 02:58 PM |
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I couldnt get my original zetec fan switch to work so i used one in the polo rad.
Im sure iv got it to swtich the earth not the feed.
If theres continuity through it all the time when disconnected its gotta be a dodgey switch. It should on have continuity through it when its at the
operating temp.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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the_fbi
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| posted on 31/7/08 at 08:24 PM |
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quote:
Originally posted by Paul TigerB6
quote:
Originally posted by robocog
Thought the Zetec used 2 temp sensors on the thermostat housing that when the ECU detects a certain temperature the ECU turns the fan on ?
Temp sensors = different resistances at different temperatures
There is one at the top - this as far as I understand is the temp sensor for ECU and the one at the side (under the hose outlets) for the dash
gauge
[Edited on 31/7/08 by robocog]
The above is 100% correct as fitted to the original donor car with the top sensor feeding the original Ford ECU.
Actually it depends which car it came out of.
A 2L Zetec blacktop from a Focus may have had the radiator fan switch cable tied to the battery tray and not actually in any pipes.
Ford did this cludge so as to control under bonnet temperatures better, switching the fan on if things got too hot, irrespective of coolant
temperature.
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