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fan relay problems

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90BCk5

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ok so heres the deal, ive got two taurus fans (pullers) rigged up on my blazer and wired up using a painless thermostat/relay kit for chev small block. now the instructions say that i can run 1 or two fans as long as the combined amp draw for both is not over 30amps. now my problem is that when i hooked everything up and fired them up all was fine. now i cant get the bastards to work.
does anyone know what the amp draw on 2 ford taurus fans is???

i've checked all my other connections, my batteries are both charged, connections tight..... is it possible ive cooked my 30amp relay:doah: and need a
mo' bigga one??

thanks
 
i would run 2 relays, if you are goign to run 2 fans

if they arent working at all now, check your fuses, might have blown somtheing
 
I'd bet they're pulling at least 15 each... You more than likely popped the fuse powering the relay...

You can check your amp draw by taking the power lead for the fan attach it to a multimeter, put the other meter lead to the positive battery post, with your meter set to amps... It'll run, showing amps drawn.. Just check max amp on your meter, alot are only 10 amp...

But I definitely would be running 2 relays...
 
i believe a single taurus fan will draw 31 amps on high.

i put 1 in a s10 blazer with a 350 useing a 30 amp relay for low and a 45 amp relay for high.
 
They are probably not going to pull 30amps.
They are probably somewhere around 6-8/piece. On a hot day with undersize wiring, mabey 10-12amps at startup (elect. motors take alot to 'startup')
I would say your fine on a 30amp relay. That's what mine setup is. Bump to a 40amp relay (and at least 12ga wireing, which I think the painless kit is already) if your worried about it.

But your relay could be bad.What brand is it? Alot of the cheapy auto store relays are really crap.
 
big83chevy4x4 said:
i believe a single taurus fan will draw 31 amps on high.
Click to expand...

Not a chance.
Stuff rarly pulls what it's "rated" for. You need to look at things like duty cycle, startup draw..and more.
Most vehicles today come with 70-90amp alternators. Until the 90's, 60 was the norm, 40 wasn't uncommon. My '73 came with a 37amp alternator. That's for the whole vehicle, if you have 1 accessory taking 30amps all the time, you'd be in a world of hurt, electrically speaking.

Flex-a-lites biggest dual setup draws 28amps max,according to their specifications. Avgs about 20, they say. So that's 10/piece, for 2 15" fans.
 
I should go downstairs and do this.. Got a shop battery, my meter and a 2 spd Taurus fan sitting around...

Most aftermarkets have continuous ratings of 8 to 12, I've heard the Ford draws more.. Mid to high teens, depending on wiring..
 
SO go on, what are you waiting for? I got a beer I can send you....:D

You got a good meter, right? Most 'regular' meters only can measure up to 10amps.
 
Or better yet, go with what the electrical engineer did for the Tarus.
That is, pop the hood of a Tarus and see what fuse/relay they use.

Who's got a Taurus in their driveway???????????????????????????????????
 
My aching knees are afraid of the stairs... :o :haha:

Actually I just remembered I brought my meter back to work.... It does 25 amps iirc..

You may very well be right... This is just internet hearsay, I'm reporting.. I'm guessing it's at least 10....

I've also heard the ones out of Lincolns are better...
 
sounds good, ill go try testing my fans, that is if i can find my voltmeter after moving:confused:....

so yeah, who's got a taurus in their driveway anyhow???
 
this is what i was told after we kept blowing 30 amp relays for the HI side of the fan. went to a 45 amp relay and the problem went away. :dunno:
 
73k5blazer said:
But your relay could be bad.What brand is it? Alot of the cheapy auto store relays are really crap.
Click to expand...

oh, and the relay is whatever came with the kit. i was just looking for it on their site but cant find my kit...
 
73k5blazer said:
Not a chance.
Stuff rarly pulls what it's "rated" for. You need to look at things like duty cycle, startup draw..and more.
Most vehicles today come with 70-90amp alternators. Until the 90's, 60 was the norm, 40 wasn't uncommon.
Click to expand...

Ouch.
http://www.fordmuscle.com/archives/2003/02/electricfan/index.php

I can't vouch for their testing methods, it sounds like that fan draws WAY too much on startup, but there are some numbers. Just looked at those and "Taurus" in the article, so no idea what else it says. :)
 
Well, I stand corrected. My humble apologies.

That said, that's just insane!, not to mention just stupid. No wonder Ford is going bankrupt. That article also says the fan pulls 2000cfm. Not sure how they tested that. By comparison, Flex-a-lites fan, at 8-12amps, pulls 2750cfm. More amps doesn't nessisarly make a more CFM, it could just be a cheap low quality china motor. Who knows...

40amps...I still have a hard time believing it. I'd still like to see what fuse and relay is under the hood of the Taurus.

So, in order to wire 2 of these fans, based from that information, you'll need 7ga wire, which isn't normally made, so 6ga battery cable, an 80amp maxifuse, and an 80amp relay at bare minimum. Seems a little extreme.
 
This is from my Electrical engineering buddy, who works for an OEM.

An Electrical Engineer said:
For a motor, startup current is normally 3X running current so that looks to be in
line. I suspect the biggest difference is size. Some of the aftermarket fans are
huge and they can turn a monster fan slowly to move a lot of air. I would image a
tarus to have limited room in the radiator area based on the way the hood lines are.
To get the same CFM with a much smaller fan, they probably run it to beat hell. If
I remember right, aerodynamic resistance is proportional to velocity squared. So,
as you move faster, you need much more power as aerodyanamic resistance increases
exponentially.

It looks like Ford intended the fan to run at a lower speed and use less power the
majority of the time and included a high speed in case the car was in immediate
danger of overheating. I would never wire a fan to run at a 40 amp load every time
it was on. It probably sounds like a plane taking off. I don't think that its a
great fit to use a small fan packaged for a car with a small frontal cross sectional
area and run it at warp speed in your truck which has room to run a large fan at a
low speed.
Click to expand...

What's the diameter of the fan?
 
The dual fan setups GM used were not designed to both come on at the same time, with that sort of draw, it's no wonder.

Yet another reason not to run both fans at once, all the time, or use high all the time when a multi-speed fan is used.
 
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