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Discussion Starter #1
Ok, Searched long and hard, and I coulkd not find any sort of wiring harness or tips really for adding an aftermarket electric fan to our cars. I have a fan from a '90 Taurus I believe. it has a ground, low speed, and high speed wires in it. i have it all mounted but I cant keep it running, I have burnt through several switches and wiring harnesses. I bought a harness for heavy duty acc. lighting (200W, 30A) and the fuse blew on it. and i had a switch actually catch on fire earlier while i was driving. any way what kind of relay would I have to use? or how the hell would I wire this all up?

-Rog
 

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If you haven't been using a relay then that wasn't a good idea. For something like a fan that has a high amperage draw, you definitely want a relay as a switch can handle that kind of current. I think a 40 or 50 amp relay should be just fine. I'm not sure exactly how to wire it up for both low and high speed but you'd want power to the relay, then you need hookups to the fan and to a switch and also to ground. Perhaps someone else can chime in here with a more specific wiring solution.
 

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i don't think 30amp will be enough for the fan.
 

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I just checked and the fan in my 96 uses a 60 amp fuse, so you should probably get a 60 amp relay and wiring that can support that kind of current. You only need wiring that thick going from the battery to the relay and the relay to the fan. The ground should also be pretty sizeable. The switch for the relay does not need heavy guage wire though. For specific wiring instructions, I can't help you. Good luck!
 

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Go to Ebay and look for relays. There are 70 amp relays on there for $17.99. You need that and some 10 AWG wire. I will try to PM you with the wiring diagram. You will probably need a 30 amp relay as well.
 

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Ask mn12xr7 for the wiring diagram. You'll need a 70 amp relay and 10 AWG wire. I can't find my diagram. They sell them on Ebay for $17. I think you will need a 30 amp relay also.
 

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Discussion Starter #7
ok, got it all wired up, like 30 bucks later.....
ok all i had to do was go up to autozone and get a relay for 40A that has 5 prongs, though I only used four. I will get the number later for the relay in case anyone else wants/needs it. but its just too damn hot outside where I have been for the past few days working on this thing. Now I need to find some sort of thermatic switch for this thing, so I dont have to maually do it. However, I heard those are no good, so I was thinking how about a speed sensitive switch that turns on below say 20 MPH, and off above say 30? any ideas?

-Rog
 

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The Parts Guy
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roger said:
However, I heard those are no good, so I was thinking how about a speed sensitive switch that turns on below say 20 MPH, and off above say 30? any ideas?

-Rog
You might want to raise the on/off point a bit. IIRC, the stock setting is somewhere around 45 MPH. I currently have my fan shutting off at 80 MPH.

-Rod
 

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The Parts Guy
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I have no idea where you're going to find a speed sensitive switch. I'm controlling mine via the EEC.

IIRC = If I Remember Correctly

-Rod
 

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Pedal Faster
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Our cars don't have a lot of open frontal area and I think the cooling fan needs to stay on until you reach a pretty high speed. My car will overheat with the fan off and going 45 mph (I tried it, it got pretty hot pretty quick).

I just have my fan set to come on at the quarter mark on the temperature gauge (generic thermostatic fan controller), and when the HVAC is set to a mode that uses the AC compressor (tapped a wire coming off of the EEC). My fan is also off of a 3.8 Taurus, but I am successfully running it with a 30 amp fuse and relay.
 

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Discussion Starter #16
ok, So everything is working fine, then today, after work on my way home, I stop at a stoplight and I hear that the fan is not on, so i pull into a gas station immediatly to check what is up, and all the wiring is warm, but not hot, certainly no hotter than the rest of the engine bay, and i remove the wiring real quick, then rewire it exactly as I did before, and when I would throw the switch, all the relay will do is click and no power, did I blow my relay? do I have a bad fan and am just pissing away time and money? a real diagram would be helpful, even though Iam almost positive I am doing this correctly.
-Rog
 

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Discussion Starter #17
oh and the relay is a 5 prong, w/ 30, 85,86,87, and 87a( I did not use 87a, if I remember). standard 30/40A auto relay.

-Rog
 

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The Parts Guy
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If the relay clicks when you turn the switch on, then it is supplying power to the fan. You can doublecheck this with a test light on the leads to the fan. Make sure the fan is receiving a good ground.

-Rod
 

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I have to agree with racecougar. If it clicks it should be providing power to the fan. With my extreme knowledge of relays, I also know that the contacts may have gone bad and are not closing all the way or at all and you have no 12Vd.c. to the fan. If you had a meter and could test each connection point on the relay you would know more. I don't use test lights. I have 4 Fluke meters. 2 for work, 1 for home and 1 for the car.
I see you are in Marble Falls. How far is it away from Houston? Where is it?
 

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Discussion Starter #20
IDk, but on my way to work today i snagged a new relay, 11 bucks even. put it in and it started right up. i guess the relay was just bad. marble falls is about 45 min North of Austin. so from houston, about 4-5 hrs. Gotta love that Texas heat huh?
-Rog
 
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