93 LX Hi/Lo Cooling Fan Problems | Ford Escort Owners Association (FEOA)
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93 LX Hi/Lo Cooling Fan Problems

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by Paul A., Jul 28, 2020.

  1. Paul A.

    Paul A. FEOA Member

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    Hello its been a few weeks since I have been online. Ive went through a big move and my car began overheating mid way through it. Ive ruled out headgasket, water pump, thermostat, faulty fan motor, faulty fan relays, and the wiring between everything. My issue is when I am driving the fan never comes on except for when the air conditioner is on. Occasionally it comes on by itself without the AC. I tried replacing the fan switch with no luck. Metered all wiring and checked the 2 relays by the air box for proper operation. Even so, when it comes on it only runs on low speed. When I unplug the connector to the switch the fan kicks on very high and I can drive the car all day in high heat and traffic with no overheating. I'm at a loss as to why it is not kicking on high by itself. Other than the PCM I cannot think of anything else that would be going bad. I don't know of it matters too much this car does have AC and it works well except for when the overheating conditions occur, it begins to blow hot. It seems like it may be associated with the fan not kicking on high. The last few times I have ran into this issue I stopped and checked to make sure the fan was running. It was running every time, but only on low speed. I cannot seem to make it turn on high by itself. I could always add a toggle switch to manually control it, but I would prefer the car works as it was designed. Not to mention if the wife drove it, she would never remember. Any help would be appreciated.



    Thanks,

    Paul

    Edit: I forgot to mention above that I have recently had grounding problems with that wack connector on the negative lead. I understand that this is the ground for the PCM among other things. Would any of that directly affect my fan like this? Also reading up it sounds like the AC should kick my fan on high, when I turn on the AC it kicks on low.
    Last edited: Jul 28, 2020
  2. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    What exactly do you mean by overheating?
    It seems these cars are designed to run really hot before the fan kicks in, I believe 230 degrees was mentioned in a recent post. The gauge on my car goes to the "L" of normal before the fan comes on, which got me quite concerned the first time I saw it.
    I like you idea of putting in a manual switch.

    You could also leave the AC on at the minimal level to keep the fan running, if that works.
    My car doesn't have AC so I don't know if it does work, but it does on the wife's Honda.

    I believe the fan is designed to run only on low to cool the rad, high is to draw extra air through the AC condenser as well.
  3. Paul A.

    Paul A. FEOA Member

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    I did notice it runs seems to run very hot. It will try to get up to the H but I usually stop once it passes the l in normal. I ruined a very nice Impala by overheating it several years back and am weary to let it go any hotter. Do you know how the fan switch operates? Ive found some good help on here trouble shooting the wiring and relays but not that 2 pin coolant switch next to the coolant gauge sensor. I tried grounding the pins to see the function of each one but it did nothing. Shorting them does nothing. I don't wanna hurt the computer although I feel like it may be problematic in regards to other grimlins Ive been chasing down. Could there perhaps be a different sensor or some wires so switch around that would allow it to kick on high without having the AC? The low setting is just not cutting it with these NM summers.

    Thanks,

    Paul
  4. zzyzzx

    zzyzzx FEOA Member

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  5. zzyzzx

    zzyzzx FEOA Member

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  6. Paul A.

    Paul A. FEOA Member

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    That is a good video however I was confused when he was testing the sensors. It appeared he was testing the one for the guage and not the fan? Are they interconnected?

    Thanks,

    Paul
  7. zzyzzx

    zzyzzx FEOA Member

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    Correct, they are separate sensors in that the gauge has it's own sensor yes.
  8. Paul A.

    Paul A. FEOA Member

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    Do you know how the 2 prong one works? Ive tried grounding each prong with no signal from the pcm to turn the fan on. Also shorting the. Together doesn't do the trick.


    Thanks,

    Paul
  9. zzyzzx

    zzyzzx FEOA Member

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    The two prong one connects to the PCM. I would put a variable resistor in it's place and adjust it to simulate an engine warming up.
  10. Paul A.

    Paul A. FEOA Member

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    So I tried simulating it with some different values ranging from approx 15 ohms to 1000 ohms. The pcm doesnt seem to ever want to signal the relays off to turn the fan on. At this point I'm gonna chalk it up to a failing PCM. My main question is can you adjust or reflash them, or should I just replace?
  11. zzyzzx

    zzyzzx FEOA Member

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    You are far more likely to have a wiring or connection problem than a PCM issue. I will consult the factory service manual to determine if 1000 ohms was enough.
  12. zzyzzx

    zzyzzx FEOA Member

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    Are you in need of a schematic?
    There are two PCM outputs, one to ground the coil to each of the fan relays. If you have a fan coming on at all, at least the PCM is partially working. There is also the starter motor cutout relay that is in the fusebox. Did you check that one yet?

    And, if for some reason, you still think it's a PCM, watch this first:



    Did you check the fan motor ground?
    Did you verify that one side of the 3 relays coils always have 12V with the ignition on?
  13. zzyzzx

    zzyzzx FEOA Member

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    What year Escort and how many sensors are on that heater hose line?
  14. zzyzzx

    zzyzzx FEOA Member

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    Check for codes and report back.

    Also check the ohms on the engine coolant temperature sensor with the engine cold and hot and report back.

    Exactly what did you do with the battery ground node? Please post a picture of it.
  15. marclar

    marclar Moderator Staff Member

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    ill read through this tomorrow, but the fan doesn't come on until around 230*

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