Electric Fan Wiring - Advice Needed

Thread in 'Technical Questions' started by tippers, Jan 6, 2012.

  1. tippers

    tippers Active Member

    Joined:
    Aug 17, 2010
    Posts:
    1,472
    Likes Received:
    0
    Location:
    Bristol
    Hey all,

    I'm fitting a pair of electric fans to my 13 this weekend, and I have got myself a thermostatic fan controller as well.

    My question is, should I wire both fans to be switched by the fan controller, or could it be worth having one wired using the controller and one on a switch on the dash. This way I can manually control of one fan and have the other fan on automatic control?

    I would have them both on a switch, but I'm forgetful and the controller should stop me frying things.

    I was looking for peoples experiences on this, as I am unsure what to do.

    Any help would be greatly appreciated.
     
  2. Dori-points

    Dori-points Member

    Joined:
    Jan 5, 2012
    Posts:
    119
    Likes Received:
    0
    Location:
    Midlands
    The last electric fans I installed (pair) I ran off a thermostatic fan switch... However it was just for road, electric fans on race cars have been either switched via a dash switch or on all the time when the cars fired. Tbh I'd stick with the viscous and cowl on a 13 though, you can't better it!
     
  3. Dori-points

    Dori-points Member

    Joined:
    Jan 5, 2012
    Posts:
    119
    Likes Received:
    0
    Location:
    Midlands
    Maybe fit one on the controller and one on a switch and wire a warning light to go off at a pre set temp to remind you to turn the other fan on?? Just a thought!
     
  4. davey

    davey Active Member

    Joined:
    Oct 28, 2010
    Posts:
    2,748
    Likes Received:
    1
    Location:
    a workshop in bristol
    +1 on the viscous fan dude, you wont beat it tbh, we used the same set up with switchs on the gen1 rx7 v8 turbo we built in work and tbh if there was any way that a viscous could've been used, we would've.

    i know thats shit advise as youve already spent the money to but the fans and switch but seriously, sell them on and refit the viscous, or keep one fan, mount it the other side of the rad and put it on a switch, just an idea :nod:
     
  5. ElTorro

    ElTorro Commie bastard

    Joined:
    Aug 12, 2009
    Posts:
    678
    Likes Received:
    0
    Location:
    Land of bears and vodka
    I did a simple thing in my Lada: in-car switch parallel to thermostatic one. You can either let the thermo do its job or switch them on manual.

    Just remember to use relay because thermostatic switch nor in-car switch wouldn't cope with high current while starting two big electric motors. Maybe some proper spec motorsport ones would, but it's simpler to do this the right way.
     
  6. 4_Stroke

    4_Stroke Member

    Joined:
    Jul 29, 2011
    Posts:
    414
    Likes Received:
    0
    Location:
    Leicester
    Put them both on the controler and parallel up with a manual switch. That way you can switch either way. The benefit if electric fans is the ability to keep cool air circulating after shutting down a hot engine. After you stop an engine water keeps circulating due to the syphon effect so it can be a benefit to keep cooling the rad, especialy on a turbo engine.
     
  7. captain_chaos

    captain_chaos Member

    Joined:
    Nov 14, 2009
    Posts:
    867
    Likes Received:
    1
    Location:
    Houghton-le-Spring
    sorry for jumping in....but could you guys explain how to wire in the switch parallel to a controller via a relay please.
     
  8. 4_Stroke

    4_Stroke Member

    Joined:
    Jul 29, 2011
    Posts:
    414
    Likes Received:
    0
    Location:
    Leicester
    It depends what kind of controler you have. if it operates on the earth side of the relay just run another wire to eatrh through the switch. If it operates on the +12v side do the same but switch through a 12v supply.
     
  9. FireStorm999

    FireStorm999 Active Member

    Joined:
    Dec 27, 2008
    Posts:
    4,305
    Likes Received:
    0
    i removed the viscous and cowling for several.

    my engine really doesnt get hot enough to worry keeping it
    my cowling was damaged.
    i wanted to free up some engine power along with getting light weight pulleys and removing AC
    i can cool after the car has been turned off
    Can turn on/off at will

    i have two 12inch fans wired up to a relay and a Rocker switch with missile cover on the dash next to fog switch, my temp still remains low, but i can turn it on and off at will, unlike a viscous.

    [​IMG]
     
  10. ElTorro

    ElTorro Commie bastard

    Joined:
    Aug 12, 2009
    Posts:
    678
    Likes Received:
    0
    Location:
    Land of bears and vodka
    Basically, you have 4 contacts on relay. One pair is for "main circuit" and other is for control signal that opens "main circuit".

    Main circuit is simple: 12v -> relay -> fans -> ground. That's the thing you want your relay to control i.e. switching on the fans.

    Control signal is not complicated too: 12v -> switches (solder your in-car switch parallel to thermostatic controller) -> relay -> ground. That's the thing that controls your relay.

    I hope I remembered the sequence correct. :wack:

    edit. works for thermostatic controller that just simply closes the circuit then reaching desired temperature. I have no idea if there are other types.
     
    #10 ElTorro, Jan 6, 2012
    Last edited: Jan 6, 2012
  11. GB / John

    GB / John NDC Runner Up 2012

    Joined:
    Feb 2, 2008
    Posts:
    2,213
    Likes Received:
    0
    Location:
    Washington / Newcastle UK
    Positive -> fuse holder (10 amp fuse) <--> fan switch <---> feed pin on relay <----earth
    Positive --> fuse holder (25 amp fuse) <--> switched pins <--> positive wire on fan. Fan - negative wire <--Earth

    For extra switch, just send a 12v to feed pin on relay via a switch.
     
  12. Dori-points

    Dori-points Member

    Joined:
    Jan 5, 2012
    Posts:
    119
    Likes Received:
    0
    Location:
    Midlands
    Google image Search cooling fan wiring diagram - will save me drawing you some kind of fan wiring for dummies sketch!
    12v feed to a 30A relay then from the relay to the fan. Earth from the fan to ground.
    Another 12v feed bridged from your other 12v feed to the other terminal on the relay. Then run an earth from the relay to the thermo fan switch (assuming it's negatively switched) can use a switch to bridge the thermo fan switch out for a manual override??

    Simples!!
     
  13. ElTorro

    ElTorro Commie bastard

    Joined:
    Aug 12, 2009
    Posts:
    678
    Likes Received:
    0
    Location:
    Land of bears and vodka
    Yeah, I forgot about fuses.

    I fused just main circuit though. The current on control circuit is very small, but you can fuse it too.
     
  14. Dori-points

    Dori-points Member

    Joined:
    Jan 5, 2012
    Posts:
    119
    Likes Received:
    0
    Location:
    Midlands
    Wow All together now...
     
  15. tippers

    tippers Active Member

    Joined:
    Aug 17, 2010
    Posts:
    1,472
    Likes Received:
    0
    Location:
    Bristol
    The reason I got the fans is because I was offered them cheap, and the IC pipework needed chopping about as the pipework to my ICV caught on the viscous for some reason.

    The cost if the fans and controller was cheaper than having the pipework modified. That's why I have decided to go this way.

    Thanks for the advice, if anyone has any more please keep them coming.
     
  16. captain_chaos

    captain_chaos Member

    Joined:
    Nov 14, 2009
    Posts:
    867
    Likes Received:
    1
    Location:
    Houghton-le-Spring
    Sounds fearly simple :) thanks for all the advice people :) just need to have a play now :)
     
  17. tippers

    tippers Active Member

    Joined:
    Aug 17, 2010
    Posts:
    1,472
    Likes Received:
    0
    Location:
    Bristol
    Righto, fitted the stuff the other day, just want to check the wiring is correct as I cannot find much on wiring a pair of fans in.

    I am going to run both fans off the controller with a 30amp in-line fuse on the power wire.

    Will wiring this way allow the relay for the controller to provide enough power to both fans without causing damage or kersploding, or should I wire in a second relay, in-line with one for the controller, to provide a separate power source for the second fan?
     
  18. GB / John

    GB / John NDC Runner Up 2012

    Joined:
    Feb 2, 2008
    Posts:
    2,213
    Likes Received:
    0
    Location:
    Washington / Newcastle UK
    2nd relay I would think would be best, 2 fans would blow a 30amp fuse.
     
  19. onsperformance

    Joined:
    Sep 11, 2011
    Posts:
    177
    Likes Received:
    0
    put a re-lay in, most switchs are only 20amp rated witch the re-lay will protect
     
  20. Dori-points

    Dori-points Member

    Joined:
    Jan 5, 2012
    Posts:
    119
    Likes Received:
    0
    Location:
    Midlands
    cooling fan wiring diagram - Google Search

    Replace temp sender with toggle switch or controller depending which fan or what your doing?? I ran 2 slim line fans from a single 30A relay switched with a temp switch.
     

Share This Page