sprayed8

iTrader: (1)

i went to the tracktoday and i gained a litle under 2 tenths with the only difference from last week being the new fans. might have gained more, last week it was colder, i had half as much fuel in the car and a gallon of race gas so that should count for a little.

greg2575489

Do they make a harness for the electric fans that link up with factory wiring on an 04 sierra?

eallanboggs

iTrader: (1)

I've used the Flex-a-Lite dual fans on an 04 Silverado(until it was killed by my wife) and then in an 04 Sierra with no problems. The Flex-a-Lites have the solid state controller which ramps up the fan speed as the water temp increases. I don't think the OEMs have this feature. The factory fans are either ON(100%) or OFF. With the solid state controller you have solid state relays rather than electromechanical. This is more reliable. I don't see where the need for an aftermarket harness came from. I made my own harness and never had a problem. I'd put the quality of my harness up against that of any aftermarket one. I solder every connector and terminal and I use shrink tubing. I use these methods on my boat which runs in saltwater constantly and I can't have problems with corrosion or loose crimps. Crimps should not be used in an environment of heat and vibration(internal combustion engine) and certainly not around rain water expecially near the Gulf or the ocean. I did have to make one modification to the solid state controller. The fans would not turn ON at a temp low enough for my satisfaction. I wanted the fans to come on at 185, but as designed would not turn ON until the water in the radiator was nearly 200. I used Ohms law to calculate the resistance I needed to add to the controller sense contacts to fool the controller into thinking the water temp was 200 when it was actually the lower 185 I wanted. I jumped this resistor across the sense contacts and did the final adjustment with the temp potentiometer. This setup never failed me. If you know how to make a good mechanical and electrical solder connection you can make your own harness for these fans or for anything else you want. My water temp stays at 185 unless I'm in stop and go traffic in the summertime with the A/C ON. In that case the water rarely reaches 200.

RandomHero

iTrader: (24)

That sounds really nice an all but there have been a lot of people who have had the Flex-a-lite controller fail on them. I've only heard of one person who had a set of ls1 fans fail.

Also with a factory set of fans, you can tune them to come on at any temperature and come off at any temp. You can also add a pcm pin to have them come on at a high and low setting. The factory fans also only enable one fan for when the a/c compressor is on.

greg2575489

RandomHero, please elaborate on how to do this. I have an 04 sierra that I have added factory fans. The GM dealership has no idea about a pcm pin. Can you please elaborate.

RandomHero

iTrader: (24)

Basically there is a pin on the pcm that is used to control electric fans. Even trucks that came with a clutch fan have it. Nelson Performance and DLH2006(or whatever his name is now) sells an electric fan harness that works with GM electric fans. Basically it has a power wire to power the fans, a ground wire, a wire that you splice into the a/c wire(to control fans when a/c compressor is used), and a wire that connects to the pcm using pin 42(I believe that's the number).

After you do that, you'll need a tune to turn on the fans. The pcm otherwise won't know at what temperature to turn the fans on and off.

greg2575489

Gotcha Randomhero. Thanks for the info. Who would be a good person to tune the pcm around Dallas area? Do you know?

howard quick

I installed fans on my 98 Burb..in which I installed a 99+ LS1 PCM and I control the fans with that.
Pins 42 (Low speed - Blue I think) and 33 (High speed - red) from memory.
Works great!

eallanboggs

iTrader: (1)

At what temp does the PCM turn the fans on? Do you just run one fan up to a certain temp or do the fans have two sets of windings? I guess when the A/C is ON you're at Hi spd.? Is this Nelson harness used to convert a flex type fan to an LS elec fan setup? I must have been confused because I thought people were using it on the Flex-a-lite dual fans with the solid state controller. With those fans you must make up your own wiring harness even though the fans themselves are custom made to fit the Silverado. I'd be willing to bet the problem people are having with the Flex-a-lite has more to do with the wiring harness you are required to make yourself rather than the solid state controller. You have to have clean tight connections because those fans draw a lot of current. If the terminals aren't tight or you don't have good grounds you're going to have problems.

howard quick

I'm using a 3 relay setup wired in a series/parrallel configuration.
Both fans on low speed then at the correct temp or with A/C both fans on high speed.

{G1203} Type Of Fans Fitted To vehicle Series Parallel Fans
{G0901} Fan #1 Turn-on Temp 93.007813 °C
{G0902} Fan #1 Turn-off Temp 91.015625 °C
{G0903} Fan #1 Turn-on By A/C Temp 0.000000 °C
{G0904} Fan #1 Turn-off Speed 48.280335 KMH
{G0905} Fan #1 Turn-on Speed 28.968201 KMH
{G0906} Fan #1 Turn-on Delay 0.250000 Seconds
{G0907} Fan #1 Turn-off Delay 0.062500 Seconds
{G0908} Fan #1 Minimum On-Time 50.000000 Seconds
{G0909} Fan #1 Run-on temp 96.015625 °C
{G0910} Fan #1 Run-on time 120.000000 Seconds
{G0911} Fan #1 A/C Pressure Enable 1482.642530 kPa
{G0912} Fan #1 A/C Pressure Disable 1310.273553 kPa
{G0913} Fan #2 Turn-on Temp 96.015625 °C
{G0914} Fan #2 Turn-off Temp 93.007813 °C
{G0915} Fan #2 Turn-on Delay 0.250000 Seconds
{G0916} Fan #2 Turn-off Delay 0.062500 Seconds
{G0917} Fan #2 Minimum On-Time 30.000000 Seconds
{G0918} Fan #2 A/C Pressure Enable 2399.699354 kPa
{G0919} Fan #2 A/C Pressure Disable 1896.058749 kPa
{G0920} Fan#1 and #2 Both Off 104.607392 KMH