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Discussion Starter · #1 ·
94 ford escort 1.9 lx wagon,
Radiator fans will not turn on. When I disconnect the 2 wire temp sensor/ switch the fans turn on. So the fans are good the relays are good. I took that 2 wire coolant temp sensor out and took it down to autozone and it tested fine. I have checked alll of the wiring and everything seems fine. I don't get it.
Is the engine computer the only other thing that could be bad, that would cause this problem?
 

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Discussion Starter · #2 ·
Another thing,
My tempature gague works fine, so that means that the 1 wire temp sending sensor is fine.
 

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Is it overheating? The fans don't come on unless you're running your A/C or your about 3/4 up the temp guage. If the fans come on when the A/C does, and you're not overheating, you're doing fine.

Matt 8)
 

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Nein.

The two wire is for the temperature gauge. The single wire is for the ecu to know when to turn on the fan. If you have a/c, check if the fan turns on with the air conditioning. If it does then its the single wire for sure. Same thing happened to me.
 

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Discussion Starter · #5 ·
StealthStyle,
Are you sure that the single wire temp sending unit is the one that sends the parameters to the computer to dictate when the fans turn on and off?

If so then why does the tempature gauge still work when I unplug the 2 wire temp sensor, and the fans turn on?

Does the computer revert to using the parameters from the 2 wire sensor?

Also I don't have AC; and yes it will overheat.
 

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Discussion Starter · #7 ·
No the fan does not turn on at all.
I think I have check everything except for the computer.
I have tested and verified that all of these components are good:
-fan motor
-fan relays
-2 wire temp sensor
-wiring
 

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Discussion Starter · #9 ·
It works!!!

I checked the ecu sensor with an ohm meters and testing at different tempatures. Like I would test it with my hand wrapped around it and then test it with out my hand around it (the heat from my hand warms the sensor up). It is a test Autozone has in their books.

Ok, after I replaced the 1 wire temp sensor and waited until it nearly overheated the fans kicked on. I replaced the 1 wire sensor hoping that there was a faint possiblity that it might be the problem but hind sight I don't think I waited long enough for the fans to come on. They turn on as the temp needle gets to the end of the "L" on NORMAL. I am thinking that replacing the ECU with a new one, will probably make the fans turn on faster.... what do you guys think.
What have others of you done to make the fans turn on at lower tempatures?
 
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