Yellowbrother

iTrader: (2)

in the oem setup...it's dual fans rite??? pcm will send signal for low speed...if need be then it will send signal for high speed??? am i correct so far??? if so...when at high speed...is both fans running high speed??? or pcm is sending signal for hi and lo at once which causes one to run low speed and other to run high speed???

i found old thread that someone posted on here on how to wire up dual fan...well i have single taurus fan with dual speed...and from what i can tell reading the schematics...its not really gonna function correctly with a dual speed fan...

http://img230.imageshack.us/img230/3...ingfansbu6.gif

in the mean time i will research taurus fan wiring...i want the pcm to control the fans...and it seems so far everything i've found on the net is people running a seperate temperature controller to control the fan...

LS1MCSS

iTrader: (18)

To use the Taurus fan, you will need a seperate controller. If you want the pcm to control the fans then you're better off with a dual fan setup. As far as one fan or both fans running, I would think that both run on low speed and then both run on high speed, but I'm not really sure about that. Maybe someone else will chime in.

poconojoe

iTrader: (43)

If you used whats know as the corvette method, on low speed both fans run on low speed and on high speed both fane run on high speed. The PCM puts out a signal on the low speed output, when in low speed mode and on both the low speed and high speed in high speed mode

Yellowbrother

iTrader: (2)

can u tell me why it has to have a seperate controller??? i mean if the pcm is putting out ground when either hi/lo kicks in...can't it be implemented into relay to control as such???

something like this but replace temp switch with pcm hi/lo???

eseibel67

iTrader: (10)

Stock LS1 actually has 3 fan settings using 3 relays and 2 PCM outputs: 2 fan low, pass side only high, 2 fan high.

But your scematic looks good to me. The only question I would have is can the Taurus fan take both high and low 12V inputs at the same time, because the PCM will command both under the right conditions

CORRECTION: I see your relay 1 has a double throw. Should be good.

Yellowbrother

iTrader: (2)

im wondering if im missing something since all info ive found is people using temp switch or some kind of seperate controller....the reason y i ask if hi/lo both come on at once cuz it was critical to how i had design it with 2 spst and 1spdt relay....but the 2nd schematic i found...it wont matter if both comes on at once....cuz the first relay will open the lo fan speed circuit....

69bigblock

I also have a taurus fan Here's a link that might help
https://ls1tech.com/forums/conversio...aurus-fan.html

I have ordered this relay package and hopefully it will work, Didn't get it yet so I can't comment on how it is..

http://www.hollisterroad.com/proddet...?prod=MarkVIII



Bryan

LS1MCSS

iTrader: (18)

Here is the schematic for LS1 fan control. You have 4 wires going to the two fans. If the Taurus fan can operate with both high and low speed input, at the same time, then you can probably make it work with your diagram. Try it and let us know the result.

Yellowbrother

iTrader: (2)

the schematic will not work electrically if u're using the pcm to control the fan since it's been mentioned that both the hi and lo signal stays on while in hi speed mode....i've read that the taurus fan won't take both hi and lo being on cuz itll burn up...unless u use an external controller of some sort then that design mite work...

as for ur relay kit...i saw that too...but i don't know how its wired out...so i cant comment...

from wat i've gathered on the oem setup...correct me if im wrong someone...but it has 2 single speed fan....the lo signal would activate one fan...and if hi signal kicks on...it would run the second fan...but both fans only has one speed...so low speed = 1 fan running...high speed = 2 fan running...

EDIT....i read the whole thread...those other guys seem to have straighten out the mistake of the original solution offered...

Yellowbrother

iTrader: (2)

same diagram i posted originally...not gonna work....if i'm reading the schematic correctly...when lo signal kicks on....it'll work fine...but when hi signal kicks on...it'll power both high speed and low speed on the fan at once...possibly burning up the fan....

so far...electrically speaking...i only see the 2nd schematic i posted working correctly using the pcm or something external for the taurus fan....

question is...y are folks using the taurus fan for lsx swap not using the pcm control but instead opt for an external control???? this i cannot find the answer to yet...but i guess i'll try and find out on my own...

Yellowbrother

iTrader: (2)

got it from rx7 website...guess they've been doing what i've been asking....

69bigblock

I just got that relay kit in the mail and it is wired up nicely. I've read alot of post that say you need a 70-80amp relay for the taurus fan.

Yellowbrother

iTrader: (2)

came back from pick a part...the original fuse that came on the taurus was a 50 amp maxi fuse...i'm trying to find documentation online of how the taurus is wired but no info yet...i pulled this big green relay looking thing and it says "relay asy. eng. cool. fan contr."...there was this gray box looking thing where all the wires went into...looked it up and its some kind of controller board...maybe it's used for current control like these aftermarket units that some guys are using...

MN-Brent

There is a test that was performed by Tom Dewitt (Dewitts Radiator) on the Corvette Forum for Spal vs Mark VIII CFM and current draw. The Mark VIII drew 40-45Amps. Using a 70-75A relay is good insurance.

http://forums.corvetteforum.com/c3-t...pal-duals.html

The Mark VIII and Taurus fans use the same motor, but have different size fans and shrouds.

Ive been running the 70Amp Tyco relay for 3 summers now with great reliability, with both thermal sw control, and now PCM control on this relay.

I also recommend using a freewheeling diode set-up across the fan to dissipate E-field development when the relay shuts off and the fan keeps turning.

69bigblock

On my harness which was reworked from speartech, I have 2 wires for the primary pink/dk green and 2 wires for the secondary fan pink/dk blue. On all the diagrams I've seen there was never 4 wires for the fan control.
Instructions say that the primary fan wires,
pink goes to relay terminal 86/Dk green to 85

secondary fan wires,
pink goes to relay terminal 86/Dk blue to 85

can anyone explain this.

Yellowbrother

iTrader: (2)

dual fan setup....on low only 1 fan kicks on...on high both fan kicks on...

topdj-com

the factory diagram shows they use a series/parallel.
fan one and two are in series in low each fan turns slower as they get less voltage in series in high mode they both get full 12v. I have used a switch and grounded the low speed relay coil to activate the low series mode, but if my engine calls for high spd or parallel while I have this switch on I get a check engine light

Aceshigh

Here's a stupid question.

Which diagram will work for 2 speeds on the Taurus fan using TWO 70A relays, 1 temp sensor, and no PCM ??

Yellowbrothers 1st diagram shows the 2 temps sensors in the LS1, but I have no idea how that would work
being that both sensors send the same signal.

Yellowbrother

iTrader: (2)

post #4 should work for ya...i couldnt find a spdt 70a relay for reasonable price so i'm going to use 3 relay...

u need 1 spdt 70a relay (5 prongs) and 1 spst 30a or so cuz it for low speed (4 prongs)

FastKat

iTrader: (10)

This is news to me. Although the wiring permits one fan to be run in high speed only, I didn't know the PCM actually did it. I always thought the PCM kept the fans at the same speed - either both off, both on low speed or both on high speed.