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How to fit thermo fan bypass switch

Discussion in 'Holden Commodore How-To's' started by immortality, Feb 28, 2007.

  1. Ghost

    Ghost Donating Member

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    I just ordered a toggle switch off ebay so I'm gonna do this as well so simple and effective

    Sent From My Galaxy S2 Using Tapatalk 2
     
  2. Ghost

    Ghost Donating Member

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    Just put my switch in works a treat

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  3. MADDNE33

    MADDNE33 New Member

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    Just done this on my vs. They run a duel speedo thermo but the blue/white wire from the ecu is still there. When flicking the switch the fan goes straight to high speed :)

    Awsome write up mate. Cheers
     
  4. MajorMoFo

    MajorMoFo New Member

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    What an awesome post. Cheers saved me heaps considering the car cost me 200 bucks cause no-one could fix this problem.
     
  5. Cavaliere79

    Cavaliere79 New Member

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    Curiosity

    I have a used 98 VT, which had a relay-fan connection-battery bypass cable on it, but it was so badly attached it fell off, and being as crap as I am, can't rewire it.

    You offer assistance in rewiring/wiring in with a switch. Is that offer still available mate?
     
  6. JustMang

    JustMang New Member

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    old thread but a gold thread, thanks for the info dude.
    done it all as you explained & is working perfectly.
    cheers again.

    <a href="http://s1379.photobucket.com/user/billy_king2/media/12088077_880934908663502_5922111669718664551_n_zpsprq3ixzq.jpg.html" target="_blank"><img src="http://i1379.photobucket.com/albums/ah148/billy_king2/12088077_880934908663502_5922111669718664551_n_zpsprq3ixzq.jpg" border="0" alt="thermo fan bypass switch photo 12088077_880934908663502_5922111669718664551_n_zpsprq3ixzq.jpg"/></a>
     
  7. Low Esteem S2

    Low Esteem S2 New Member

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    Awesome mate ! Thanks ! One question though,does the thermofan and ECU go back to closed circuit/self monitor operation after you turn switch off ? I would hate to forget to turn it on one day,in traffic hahaha ! But you have stated that its a bypass switch . Other than that,so gonna do this anyways. Could maybe use a timer switch from an old microwave or washine machine LOL Cheers ! Oh also the wire guage ? Would V105 at least,heat rating wise suffice ?
     
    Last edited: Dec 11, 2015
  8. VTL67Calais

    VTL67Calais Vtl67 calais

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    Wouldnt worry about fan waring out as if you have air cond on all the time the fans on any way, in hot areas like QLD i always have aircond on, in adelaide though im thinking of fitting the thermo now the heat waves have past, GREAT WRITE UP CLEAR AND LOVE THE PICS it helps a lot.
     
  9. David Commode Door

    David Commode Door New Member

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    I've done this on my VN with a switch with led. The led lights so I'm guessing there is power and earth but the fan does not come on.

    Ideas?
     
  10. Andrew005

    Andrew005 New Member

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    Life saver, just wired one up in my Vg ute
     
  11. RUN415

    RUN415 Member

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    Hi All,

    I was driving over heavy corrugations and the air con 'popped'.
    (eg: Sudden hiss - discovered it spat out coolant from the somewhat corroded accumulator thing at the front of the radiator.)

    Not sure if it's related but a short while after that I noticed that the
    thermo fan wasn't coming on when I turned on the air con...as it used to.

    I bridged out the LO FAN fan relay and the fan came on...so it's still working ok.

    SO my question is:
    Is there any disadvantage (besides making the fan completely manual)
    to just bridging out the relay socket with a switch???


    For me it just seems easier (no splicing into wires etc) and I know it's going to work...
    ...as I must consider there is now another (air con?) fault somewhere?

    Cheers.
     
  12. immortality

    immortality Moderator Staff Member

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    There is a pressure switch in the aircon system. The PCM would see this fault and not turn on the AC pump and also not turn on the thermofan as it is not needed but that doesn't mean the PCM won't switch the thermofan on when it's required once the engine reaches the required temp. Best to test by letting the engine idle once up to temp and verify if the thermofan comes on when the engine gets hot.
     
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  13. RUN415

    RUN415 Member

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    Makes sense...and it's nice to know what's goin' on with the air con and fan.
    I thought it was probably somethin' like that.

    I'm a bit reluctant to test the PCM's ability to turn on the fan...
    ...as it's ALWAYS been way too late.
    You can 'smell' the engine starting to cook before it comes on and it stresses me out.
    I just hate doing that to my engine :")

    I'm the only one who drives the car...so having the fan on 'manual' is not a problem.
    So I'm going to proceed with my plan to wire the switch thru the relay socket.
    It's only for occasional use anyway.

    I guess I'll have to fix the air con at some stage...but it won't be any time soon.

    Thanks Immortality. Cheers.
     
  14. immortality

    immortality Moderator Staff Member

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    Completely agree. In the stock tune the low speed fan comes on at 104° C and the high speed not until 108° C which is just bloody ridiculous. The best fix is to have the tune adjusted so the fans come on a lot earlier. On our L67 I run a 82° C thermostat and have the thermofans set to come on at 86° C staged (so there is a couple of seconds delay before the high speed fan comes on). Engine never gets over 87° C.
     
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  15. VS_Pete

    VS_Pete Donating Member

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    As above.
    That`s what I`ve got. The1 recommended it and did tune.
    Temp hardly moves.
    THERMOSTAT DAYCO 82° C
    Part Number DT22A
     
    Last edited: Oct 6, 2018
  16. Deuce

    Deuce Super Stock

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    I think my tuner has set my a/c fan to come on at similar temps.
    Will log temps one day and see
     

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