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94 grand am, low coolant sensor, it works backwards ?

Discussion in 'Other Rides' started by R72K5, Jan 21, 2004.

  1. R72K5

    R72K5 Banned

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    on 94 grand am with 3100 3.1L the low coolant sensor deal in bottom of the coolant reservoir is wacked, we got a new one from napa because the original one was causing light to be on even though the tank was full to line, well the new one does same freaking thing, you unplug it and light goes out, you plug it in with full tank and it comes on

    hum..

    and also does anyone know at what temp the ECM coolant fan temperature
    sensor switch will tell the ECM to turn on engine cooling fan relay and fan ?? got it up to about 207 or 208 F and the fan still never came on with new coolant temp switch even- (not the coolant temp switch for guage in dash) and engine wont get any hotter than that idling in the garage, so hmm..

    i did the test according to manual about unuplugging the temp sensor plug and crossing the two terminals/wires with key on and the fan is supposed to turn and the fan did spin but not very fast, not even fast enough to move any real air, and but the relay did click, so that rules out relay problem, but what about the fan motor, why does the fan not spin like its supposed to like the manual says it should ? doesnt spin on its own at all after we put new sensor in but then it didnt get over about 207 F or so.


    i appreciate any answer with any info about either phenomenom



    thanks
     
  2. Confedneck

    Confedneck 3/4 ton status

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    coolant sensor, on the connector, is there 2 seperate connections? if you have them crossed, it will work in reverse.. if one of the wires is grounded, or the connector has a lot of corrosion then it will ground out and close the circuit..

    did you try turning the a/c on MAX and HI to get the cooling fan on? i would still try swapping a relay, because a weak relay could cause improper current flow, in return not allowing the fan to run at its full potential..
     
  3. R72K5

    R72K5 Banned

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    not two separate, only plugs one way and not any other,

    interesting on the relay, hmm.,. figured that it either worked or didnt work hmm..

    also wouldnt the fan at least spin real slow like it was doing when testing the sensor ?

    thanks
     
  4. R72K5

    R72K5 Banned

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    how do i find out, ?
    this is why i posted this in the freaking lounge, because in this board here other rides ive only got three views! and i need to find this out someway somehow and ASAP!


    ............


    thanks
     
  5. Confedneck

    Confedneck 3/4 ton status

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    and if you take the connector loose, does the light go off? or if you take it loose and jump it with a paperclip does it go off? if so.. then the sensor is still bad.. if not then you have a wiring problem..
     
  6. HarryH3

    HarryH3 1 ton status Author

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    The temp sensor doesn't decide when the fan will kick on. It just tells the ECM what the engine temp is and then the ECM decides when to turn on the fan. The turn-on temp is programmed into the PROM. It should also come on when the a/c is running. But the a/c has to be functional for this to work. A switch on the high pressure side of the a/c closes when the pressure rises, grounding the a/c request pin on the ECM. That should turn on the fan and also bump the idle slightly so that the drag of the compressor doesn't stall the engine. /forums/images/graemlins/cool.gif

    Some vehicles have an aux fan that is turned on by a thermoswitch, independent of the ECM. On these, Fan 1 is controlled by the ECM and Fan 2 is just controlled by a thermoswitch that is set to come on when the engine is 10-15 degrees hotter than the stock ECM setting for Fan 1.
     
  7. R72K5

    R72K5 Banned

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    awesome i appreciate it /forums/images/graemlins/laugh.gif
     
  8. dave_90_blazer

    dave_90_blazer 1/2 ton status

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    for the coolant level light, tap on the side of the res. with a screwdriver handle, it is common for the sensor to stick low if you drain or run the coolant low
     

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