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electric fan wiring help

lak2004

lak2004

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I have the windstar fans in my blazer and the Jegs wiring kit with a 195* thermo switch. I wired it up just how the instructions stated but the fans do not come on unless I manually switch them. I am not sure what is happening but I know the thermo switch is good. This is how they stated to wire it:
relay: 30-Battery 12V
85-Thermoswitch
86-12V+ Ignition
87-Fan +
 
Last edited:
Ok so found something interesting. Do you need to split the thermo switch to the relay and the fan?

Like this:

efaninstall1.gif
 
Is your switch there to override the thermoswitch to force the fans to come on or to disable them so they don't come on in a water crossing?

If you want to force them on, use that diagram but make your manual switch ground terminal 86 BEFORE the thermoswitch to turn the relay on.

If you want to disable the fans totally then make your manual switch prevent power from reaching terminal 85 when you want them disabled.
 
Thats how I plan on wiring a switch, but I would like my big fan to come on with the thermo switch and have control of the smaller fan with a switch. But I cannot get the thermo to work? I know I can wire it in to a switch, which is how I used to have it and I just had to watch my gauge and remember to turn it on.
 
The temperature switch will only ground itself when the temp gets high enough so are you sure it's hot enough? Make sure you don't use pope tape on thet hreads.
 
My guage says its hot enough but it is the factory guage. I am going to get an infrared thermometer and check it I guess. I could never get it to work on my old engine either. Didnt put anything on the threads either.
 
Ok after reading a ton of info online, I believe I have this system wired correctly. I cannot figure out why it still will not work so I am thinking of going to an adjustable fan control switch for one of the fans and just a manual switch for the other.
 
Maybe your switch is bad? Try dropping it in some super hot water and see if you get continuity.

The switch grounds itself once it reaches temp so your diagram won't work without 12v to either 85 or 86.

The diagram in post #2 is the right way.
 
i thought it was right and I tested the temp switch not too long ago but i will check it again .
 
ok so i have my fan wired up as I posted in the first post. they are still not coming on. just tested voltages at the relay and this is what I have:
30: 12v
85: 12v
86: 12v
87: no voltage.

So something is not right. Obviously I am not getting voltage to my fan. This is a brand new relay as well and I know the fan works because I can turn it on with a switch. I also tested the thermo switch in water and it worked as well when I did that. So any ideas? Thanks
 
bp71k5 said:
The diagram in post 8 won't work. You need to have 12v on 87
Click to expand...

Im not using that one. Using the first one. Just to clarify I have 30-12v from batt, 85-thermoswitch, 86-ignition 12v and 87-fan +

Oh and I am also not using a switch right now. I want to try to get it to work off just the thermo switch for the main fan.
 
lak2004 said:
Im not using that one. Using the first one. Just to clarify I have 30-12v from batt, 85-thermoswitch, 86-ignition 12v and 87-fan +

Oh and I am also not using a switch right now. I want to try to get it to work off just the thermo switch for the main fan.
Click to expand...

Ah, then if your fan is properly grounded, then your temp switch isn't grounding or reaching temp.
 
:doah: I think you nailed it because I havent grounded my core support yet and that is what the fan is grounded too. I just re-did the frame and engine grounds so they are good. Thanks! I knew it would be something simple, always helps to have someone elses perspective!
 
Well my ground is not the problem. I think it is the thermoswitch. FOCK jegs stuff, everything with their brand on it i have ever gotten is crap. I am a summit customer now :thumb: . So now I am going to get an adjustable switch instead of the thermo one. One day Ill throw down the cash for the SPAL one, but for now its a probe job :D
 
You can test the switch with a heat gun or super hot water. I think I used a jegs switch.

What temp thermostat are you using? The thermostat needs to be rated for lower temp than the switch. Or is it higher?
 
Damn brian this thread is almost a year old and you are still the only one who has posted in it :haha: :doah:

Thanks for all the help though, much appreciated! :thumb:
 
Yep triple checked it. I just wired both of them up to separate switches. Just have to keep an eye on the gauge which I am already used to doing. So no big deal there. I think I will just save up for the SPAL, maybe find it on ebay for cheap.
 
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