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Fan #1 stays On

Discussion in 'Diagnosis/Help' started by vicdat, Jul 25, 2013.

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  1. vicdat

    vicdat Well-Known Member

    OK quick question...
    just over the last week or so, the left cooling fan will come on as soon as I turn the key and runs constantly. Other than that the Burpcar runs perfectly and nice and cool (of course)...I've checked all the usual suspects and all looks fine but I bet there's a simple solution that one of you brain trusts can shed some light on. Any and all feel free to chime in.
    Vicdat. '87 GT-S Auto Calif spec
     
    vicdat, Jul 25, 2013
    #1
  2. LionTR

    LionTR Well-Known Member Donated!

    Sensor can be bad, or loose connections somewhere. It's designed to let the fan go all the time if something goes wrong, to protect the engine from overheating.
     
    LionTR, Jul 28, 2013
    #2
  3. Stig

    Stig ST162 Guru Donated!

    Disconnect the waterpump sender, short the plug to ground - fan should go off. If it goes off replace the sender.
    If not check the fuses & relays, I did have this once and all it was a bad connection on on of the relays - my car has 2 fan relays
     
    Stig, Jul 28, 2013
    #3
  4. vicdat

    vicdat Well-Known Member

    Thanx Stig
    By water pump sender you mean the single spade sensor..right?
     
    vicdat, Jul 28, 2013
    #4
  5. vicdat

    vicdat Well-Known Member

    I just tried that Stig
    When I ground the spade the fan stays on; if I pull out either the relay (Fan #1) or the 30 amp fuse next it the Dan goes off so I'm thinkin that the relay is the culprit.
    Is there s continuity test for that relay?
     
    vicdat, Jul 28, 2013
    #5
  6. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    relay is not usually the culprit.

    check the diagram on the relay, it should be something like
    "run 12v across these two pins, then you won't have continuity on the other two pins that did have continuity before."
    ^ only applicable to the fan relay as it's a normally opened relay.

    also the sensor coming off the thermostat housing has a very long wire to travel around the engine bay. mine was ripped somewhere and i diagnosed that by running a wire directly to one of the pins on the relay while the relay was plugged in. once i ran that extra wire, the fans turned on/off as they should be
     
    eNtraxGT88, Jul 29, 2013
    #6
  7. vicdat

    vicdat Well-Known Member

    The relay is good
    l'll try the jumper wire directly to the relay since I suspect that there is a break in the old wire.

    Vicdat
     
    vicdat, Jul 29, 2013
    #7
  8. vicdat

    vicdat Well-Known Member

    Does anyone know if the two radiator fans are essentially the same part?
    The car is 1987 GT-S automatic (Calif car). A few months ago I replaced the #1 fan (left one). Now the original right one seems to be week (on the AC side). I will probably order one from Rockauto so I want to make sure that I get the correct one...

    Vicdat
     
    vicdat, Aug 4, 2013
    #8
  9. Mafix

    Mafix Owner Staff Member Administrator Donated!

    not the spade. that goes to the gauge. therer is a 2 wire sensor. either in the bottom of the radiator or on the thermostat housing. unplug it. start the car. see what the fan does. then stick our trusty paperclip between the 2 terminals. start the car. see what the fan does. i'm pretty sure you have a bad ect.
     
    Mafix, Aug 4, 2013
    #9
  10. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    ^ that's only on the 3s-gte. the FE/GE only has it on the thermostat housing and it's a 1-wire.
     
    eNtraxGT88, Aug 4, 2013
    #10
  11. Donavan

    Donavan Member

    Was there any resolution to this problem? I am having similar issues after doing the beams swap and keeping the beams fuse box (Normally Closed relay). Read somewhere (don't remember exactly) that the problem could be with the A/C pressure sensor(s). Check those out, I will be doing mine in the morning.
     
    Donavan, Sep 21, 2013
    #11
  12. vicdat

    vicdat Well-Known Member

    Thanx for chiming in Donovan,
    It's still doing it 95% of the time. I wouldn't be surprised if it had something to do w/ the AC because occasionally my compressor doesn't kick on (the light on the dash doesn't glow and there is only warm air)...
    Where is this pressure switch located?

    Vicdat
     
    vicdat, Sep 22, 2013
    #12
  13. vicdat

    vicdat Well-Known Member

    The Saga Continues ...

    It seems like a couple related issues have reared there ugly heads again.
    The temp gauge is spiking all of a sudden causing the car to run rough.
    Anybody have similar symptoms and what was outcome?

    Vicdat
    PS I need to get the car reliable by this weekend ...or else..
     
    vicdat, Sep 23, 2013
    #13
  14. Stig

    Stig ST162 Guru Donated!

    For the fan I'd remove the relay for now, I had this issue once and it was a faulty relay.
    I think the a/c pressure switch will only prevent the compressor from working if there's low gas.

    As for the gauge and running - I'd recommend checking all your earths (remove and re-fit) as well as the alt/a/c harness where it runs over the head. (prone to chafing)
    Also try another alternator - you may have a voltage f/up caused by a faulty regulator.

    Take it to your local battery shop and have the alt/charge/battery checked on their tester.
     
    Stig, Sep 23, 2013
    #14
  15. vicdat

    vicdat Well-Known Member

    Thanks Stig

    Which relay (there are soo many...)
    I'll have the alt checked out on the car; I have a spare one.
     
    vicdat, Sep 24, 2013
    #15
  16. vicdat

    vicdat Well-Known Member

    Hey Stig
    I just had the alt checked out and it failed on two tests (diodes & volt reg) it was still charging good and the battery is good. I also had my spare alternator checked out and it failed on all three tests.
    I bought a new alt and will be putting it in later today (they tested the new one and it passed all tests).
    Hopefully this will fix my spiking temp gauge .. maybe the fan issue too I hope!

    Vicdat
     
    vicdat, Sep 24, 2013
    #16
  17. Stig

    Stig ST162 Guru Donated!

    Don't feel bad - I've had 2 alternators blow up on me this year already and I have a new battery also.

    On your fuseboxes under the hood there should be a marking for fan1 & fan2

    Let us know if all's ok
     
    Stig, Sep 24, 2013
    #17
  18. vicdat

    vicdat Well-Known Member

    I just finished replacing the alt and that gave me a chance to clean up the wiring and tighten up various nutz and bolts. Replaced the round relay for fan1 on the fender side. That has stopped it from coming on with just the key on. Hopefully all is well again...
    Now I can tackle the front struts which are totally shot!

    Thanks for your quick response.

    Vicdat
     
    vicdat, Sep 24, 2013
    #18
  19. BogzillaGTR

    BogzillaGTR Active Member Super Moderator

    Must be an st162 thing then xD because my alt literally blew up on me and the ac pump seised up at the same time, so removed the ac pump and im now just running a shorter belt over a new st202 alternator. And my front shocks are beyond gone too !! They are literally the worest i have ever felt but no worries i am trying to get some replacement shocks asap and i just bought some brand new lowering springs today for $40 :D Which i couldnt be happier about ;)
     
    BogzillaGTR, Sep 25, 2013
    #19
  20. vicdat

    vicdat Well-Known Member

    So per Stigs recommendation I ended up re-replacing the round relay (Fan 1) on the fender side. Now all seems normal again and the fans are working properly...
    At the same time I put in a new (rebuilt) alternater. Between these two things I'm no longer getting the temp "spike", although occasionally the temp gauge will run a bit above half for a spell, especially if under a load, going up a grade, of if its hot outside. Car seems to run fine, but I think the AC has a few bubbles and takes longer to cool down; may this have something to do with the AC pressure sensor that Bogz alluded to???
    Vicdat
     
    vicdat, Sep 27, 2013
    #20
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