1991 1.9L cooling fan not working

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by 91SexScort, Jul 24, 2011.


  1. 91SexScort

    91SexScort New Member

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    1991 1.9L

    Hello guys, I have a problem also with my fan not comming on, and guage going past "L" .

    I've manually jumped the fan, and both High and Low fan speeds work.

    Also I disconnected the 2 wire harness to the ECT while the car was idling and found the fan came on.

    My A/C doesn't blow cold air, but did put it on,
    and still the fan doesn't wink.

    I haven't checked the main (cooling fan) relay, but the 40A fuse looks good.

    Is the culprit the ECT sensor ?

    Any ideas ? :)
  2. denisond3

    denisond3 Moderator Staff Member

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    Did the fan previously come on by the time the gauge had gotten to the "L"? If your a.c. system isnt okay (that is it is charged up and works), then turning it on wont cause the fan to run. The fan should run if the a.c. compressor is getting power, but the.compressor wont run if the system is too low on pressure - nor if its too high in pressure.

    When you first turn on the ignition key, the fan should spin for part of a second, then stop. Thats because the PCM has to tell one fan relay to switch 'off', and it takes almost a second for the PCM to do its own power-on-self-check.
  3. 2scorts

    2scorts New Member

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    i have never had a fan wink at me either.
  4. 91SexScort

    91SexScort New Member

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    No the fan didn't come on before it reached "L". Maybe about 2 years ago. but the car's been in storage ever since.

    I didin't hear it spin when i turn the ignition key. I do remember it doing so previous to storage though.

    Maybe the main (cooling fan) relay could be the culprit ?

    Thanks for the responses... :)
  5. Benlightnd

    Benlightnd FEOA Donator

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    my 93 does the same thing. after doing some checking, I found the car's
    temp is fine. the gauge is lieing to me about how hot the enigne is.

    Drive it be the parts store and ask them to check it with their infra-red
    gun so you'll know if things are really getting hot.

    FWIW, my fan doesn't come on until after the gauge is about and
    1/8 inch past the " L "

    Thats about 214 degrees based on the tests I did.

    Based on Ford manual, fan isn't designed to come on until 220.

    As problematic as overheating is on our 1.9's, your right to be concerned.
    BUT wouldn't hurt to make sure which problem you have first.

    Overheating or Gauge inaccurate ????
  6. ozgur

    ozgur New Member

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    In my 93, the fan stopped working and it started overheating. All of these things happened after a speed bump. It turned out that it was all about bad grounding. I wired grounding cables and cleaned the contacts and later fan came on and also the gauge started showing actual temp.

    To test the ECT sensor (next to the temp sending unit which is the gauge on the dash board). Remove the ECT sensor and measure its resistance. It should be around 10~20 k Ohms at room temperature. Then put it in warm water and measure the resistance, you should see it going down. This is to test if it is working. Second test is your contacts where the ECT goes in. Make sure they are clean. Again you can jump wires into them and measure the voltage. Escort provides ~5 volts through one connector and this voltage is applied to the ECT sensor. The other one goes to the ground through another internal resistor. The computer measures the voltage on the second connector and in my car if it is below 0.5 volts, the fan kicks in. You can test this by hooking up a variable resistor (0 to 5 k) and measure the voltage difference with respect to the ground. If the voltage difference is lower then the high speed relay works. So just by using a variable resistor and a voltmeter you can see if ECT sensing system works.
  7. Benlightnd

    Benlightnd FEOA Donator

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    The other one goes back to the PCM as a signal voltage. The PCM uses
    that voltage to determine the engines termperature. When the engine
    temp gets to approx 220 degrees, the PCM grounds pin 33 of the
    PCM connector energizing the fan relays and turns the fan on.

    http://www.feoa.net/modules.php?name=Fo ... ic&t=74620

    Your statement is very close to right. Normally, I wouldn't bother but
    this has been such an issue lately, I wanted to clarify some of your
    comments that could be misleading to those trying to work through this
    problem.

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