chevrev

iTrader: (2)

I am installing the cooling fans into my 56 chevy/LS1 project. I am using dual cooling fans from a 2002 corvette.
My wiring diagram shows that I am supposed to have 3 relays. Is that correct?
Any way to get it done with 1 or 2 or do I need all 3?

Thanks,

Rodder

iTrader: (2)

If you use 3 relays like the stock harness did, then you get a low speed and a full speed for the fans. Both fans at low speed is a LOT quieter than 1 fan at full speed, and cools better too. I originally wired mine with 2 relays (Low = 1st fan, High = 2nd fan), but once I realized what the 3rd relay did (switched the fans between "series" and "parallel"), I went back and rewired for 3 relays.

ssduane

iTrader: (3)

Does this only work for cooling fans that work that way? Like stock GM fans etc.... Or will adding the 3rd relay turn any dual fan setup into low/high setup. I have a duel flex-lite setup and was wondering if that would work.

Schitzo

iTrader: (6)

It will work with any dual fan setup as long as the relays are wired correctly and the LS1 computer is controlling the fans.

ssduane

iTrader: (3)

Sweet, thats what I was wondering. I'm heading out to the garage then.

Rodder

iTrader: (2)

It'll work with any normal pair of fans with 3 relays. For that matter, you could use two old fashioned temp switches instead of the LS1 PCM to control the relays, although if you've got the computer, might as well use it!

ssduane

iTrader: (3)

I went out and wired it up, used regular 4 pin relays for the fans and a 5 pin for the other relay, its what I had and looked like I didn't need the 5 pin for the main relays.

Fired her up and the fans, both kicked on at 172 degrees, according to my digital dash sending from the p-side head (rear). Engine wouldn't get over 180 degrees but seems like both fans were runnign slower. Going to grab a amp meter and see what current draw is wired up like this and straight wired.

Thanks guys!

malibu jax

Hello-

Does anyone have a photo of the relay setup that you ran for the fans. I am at the same point and just wanted to see how someone else went about the setup. Thanks

the_merv

iTrader: (88)

How does it cool better if the Fans are spinning slower if it's pulling less air through..

When I did my swap into my Camaro, I re-wired the whole Fuse Box, and wired my Fans to a Manual Setup, 2 switches, 2 Relays, High speed only.

poconojoe

iTrader: (43)

Two fans spinning at half speed will cool better then one fan at high speed, since its pulling air over more radiator surface. When it is required both fans go to high speed.

the_merv

iTrader: (88)

True.. I'll have to look into getting mine to both spin at low, then at high.

Is it hard to wire it for that, I know how to wire a Relay, you just make one circuit Parallel, then the other Series?

poconojoe

iTrader: (43)

If you have a source, to see the diagram, just wire it up the same as the 2002 corvette.
If you can't find the diagram, email me, I'll send it to you. I have it on paper, but could just save it as a PDF file and send it to you. I bought CP S10 swap radiator and am going to wire the twin fans on it that way

GA95DCMSS

iTrader: (13)

Here are the schematics for the fan wiring from a 2004 Express van. It will work the same for the F-Bodys, just have to change the PCM pins to the corresponding pins on your PCM.

ssduane

iTrader: (3)

thats the schematic I used for mine. Only thing is on the two outer relays I used the 4 pin relays (don't have 87a) because it was what I had in the garage, worked great.

Two fans on low draw a lot less amperage then the two at full speed. I idled the car the other day, 80 degrees out and the fans ran nice and quiet, engine sat at 176 degrees.

Carshopinc.com

iTrader: (5)

I just use two relays in my setups, I usually never wire for the low and high speeds. Just my feelings on things..... it's all up to how u want it to work

the_merv

iTrader: (88)

Yea, I've never had a problem with them set on constant high. With the Cutout open at Idle it kinda drowns out the Fans..

Andy1

At what temperature does the PCM switch on the low speed and then the high speed fan circuits?

If the PCM temp switching is too high, can you use two different temp switches on the motor or radiator to switch for the low and high circuits? Is there a prefered temp switch that I should look for? I noticed some turn on at say 200 degrees, then turn off at a lower temp.

Thanks a bunch,
Andy1

the_merv

iTrader: (88)

Depends on what it's set at to turn on..

Andy1

The PCM is an '01 Camaro. What are the factory temps set to for low and high?

Andy1

Andy1

ttt

Andy1