2002 GMC Sierra w/ls1 efan settings???

[DanaliHD]

I just switched from HPtuners to EFIlive and am unsure how to set the efans in the program. These are lt1/ls1 style efans using a wiring harness from nelson performance. It is wired into pin 42 of the pcm.

How do i set them up using efilive?

[350SS]

I just switched from HPtuners to EFIlive and am unsure how to set the efans in the program. These are lt1/ls1 style efans using a wiring harness from nelson performance. It is wired into pin 42 of the pcm.

How do i set them up using efilive?

I'm just learning how to use EFILive, but I believe the fan parameters are under

Calibrations/System/Fans/Parameters

[TAQuickness]

Danali - Welcome to the forum! I'm sure you'll enoy your upgrade in tuning suites. Please post up any other questions you may have.

I don't have my manuals handy to check the pinouts, but if the pin you mentioned is the same as the GM factory harness connects to, I believe 350SS has shown you the way.

[DanaliHD]

i want to use the settings under "auxilary fans" right?

[350SS]

I believe 350SS has shown you the way.

Score one for Max :rockon:


i want to use the settings under "auxilary fans" right?

I believe that is correct. C1 Blue connector pin 42. How many relays does that harness use?

[Chevy366]

Pin 42 is low speed fan trigger ground and 33 is high speed fan trigger ground from PCM .
Nelson has 3 relays , or at least they use to .
On stock fan relays the pin 42 triggers the fans to turn on low speed , Fans in series 6Vs each , then pin 33 triggers the relays to turn both fans on 12Vs each .

[DanaliHD]

why would he use pin 42 (low speed) instead of pin 33 (high speed)? these fans are being used on a 408ci motor and 80mm turbo setup. wouldn't i want the fans working as hard as they can?

[TAQuickness]

You will definately want to keep things cool to protect your investment, but the fans will indirectly increase load on the engine.

[Chevy366]

why would he use pin 42 (low speed) instead of pin 33 (high speed)? these fans are being used on a 408ci motor and 80mm turbo setup. wouldn't i want the fans working as hard as they can?

Why would you want to run puny little LS1 fans for then ?
Slap some 05 large fans on that thing .
Speed is done by relays not PCM , PCM triggers the relay as to what it wants to do LOW or HIGH .
Yeah , those Nelson harnesses are bad about causing a large load on the Alternator , which in turn causes a draw on the motor , they will suck so much power you can see your lights dim and the motor rpm lower when the fan kick on , and I don't mean a little .

[DanaliHD]

Why would you want to run puny little LS1 fans for then ?
Slap some 05 large fans on that thing .
Speed is done by relays not PCM , PCM triggers the relay as to what it wants to do LOW or HIGH .
Yeah , those Nelson harnesses are bad about causing a large load on the Alternator , which in turn causes a draw on the motor , they will suck so much power you can see your lights dim and the motor rpm lower when the fan kick on , and I don't mean a little .

hmm, so the fans from 05 silverado/sierra are better/bigger? whacky, didn't know that. how much are they?

[350SS]

I think you guys are making this more complicated than it really is. There are two fan outputs from the pcm
C1 Blue connector pin 42 low speed fan ctrl
C2 Rec connector pin 33 hi speed fan ctrl

I depends on your wiring harness/relay setup which one you need to use. The LS1 fans were setup in a series/parallel arrangement so that the fan speed could be altered based on engine temp/ac engagement so that they didn't have to run at 100% all the time. Basically pin 42 turns on the fans at low speed first and if the temp keeps increasing pin 33 will activate and cause the fans to run at full speed.

The other way that it can be wired is to use only one pcm output at pin 42, so the fans will either be on or off. It's not that if you use this output the fan speed will be lower, this is just the first trigger in series that comes on. If the nelson harness only uses one pcm trigger it would go to this pin. This is why in the fan parameters in EFILive there are different selections for the type of fans you are using.

From the menu:

"Select the type of cooling fans fitted to the vehicle, the PCM supports the following types -
1. Series Parallel Fans - Where both Fan Outputs (1 & 2) are used to control two fans.
2. Auxiliary Fan - Where just Fan1 output is used, generally these vehicles will also have a mechanical clutch fan.
3. No Fans - Only a mechanical clutch fan is fitted
4. EV Fan - Used on later model vehicles, the fan speed is variable by means of a PWM output."

What it comes down to is how Nelson wires their setup. I'm sure they would be able to set you straight on where to plug the pin(s) in at.

[350SS]

Why would you want to run puny little LS1 fans for then ?
Slap some 05 large fans on that thing .
Speed is done by relays not PCM , PCM triggers the relay as to what it wants to do LOW or HIGH .
Yeah , those Nelson harnesses are bad about causing a large load on the Alternator , which in turn causes a draw on the motor , they will suck so much power you can see your lights dim and the motor rpm lower when the fan kick on , and I don't mean a little .

Just for arguments sake, I'm pretty sure there are plenty of trucks out there using LS1 fans w/ no cooling problems. And as far as the Nelson harness causing a large load on the alternator, I think that has more to do with how much amperage the fans draw than anything else.

[Chevy366]

I think you guys are making this more complicated than it really is. There are two fan outputs from the pcm
C1 Blue connector pin 42 low speed fan ctrl
C2 Rec connector pin 33 hi speed fan ctrl

I depends on your wiring harness/relay setup which one you need to use. The LS1 fans were setup in a series/parallel arrangement so that the fan speed could be altered based on engine temp/ac engagement so that they didn't have to run at 100% all the time. Basically pin 42 turns on the fans at low speed first and if the temp keeps increasing pin 33 will activate and cause the fans to run at full speed.

The other way that it can be wired is to use only one pcm output at pin 42, so the fans will either be on or off. It's not that if you use this output the fan speed will be lower, this is just the first trigger in series that comes on. If the nelson harness only uses one pcm trigger it would go to this pin. This is why in the fan parameters in EFILive there are different selections for the type of fans you are using.

From the menu:

"Select the type of cooling fans fitted to the vehicle, the PCM supports the following types -
1. Series Parallel Fans - Where both Fan Outputs (1 & 2) are used to control two fans.
2. Auxiliary Fan - Where just Fan1 output is used, generally these vehicles will also have a mechanical clutch fan.
3. No Fans - Only a mechanical clutch fan is fitted
4. EV Fan - Used on later model vehicles, the fan speed is variable by means of a PWM output."

What it comes down to is how Nelson wires their setup. I'm sure they would be able to set you straight on where to plug the pin(s) in at.
Isn't that what I said with far less words?

[Chevy366]

Just for arguments sake, I'm pretty sure there are plenty of trucks out there using LS1 fans w/ no cooling problems. And as far as the Nelson harness causing a large load on the alternator, I think that has more to do with how much amperage the fans draw than anything else.
Did not say he would have cooling problems , just why run two fans on high when you can do the same cooling with two on low (05 larger more CFMs).
I have went through all this with mine , so been there done that .

[350SS]

Isn't that what I said with far less words?

Well, considering that this was the response:


why would he use pin 42 (low speed) instead of pin 33 (high speed)? these fans are being used on a 408ci motor and 80mm turbo setup. wouldn't i want the fans working as hard as they can?

your explanation didn't exactly hit home. :cheers:

[DanaliHD]

the guy tuning my truck tried using the parallel setting and the aux settings and the fans don't work. They DO however work when hard wired. Should I assume one of the relays died or maybe the pin came out of the pcm? He's checking both. I'm just trying to stay 1 step ahead

[Chevy366]

Well, considering that this was the response:



your explanation didn't exactly hit home. :cheers:


Yeah pin 42 has to have a pin , must have came out as you said .

I took it he already knows as it was explained to him when he received the Nelson harness , Nelson tells people to use the pin 42 on the PCM for the fan harness , explains how to remove connector and insert pin supplied .

Be sure and put you a 30amp fuse on the power wire , I don't think Nelson does that but is a good idea anyways.

[350SS]

I was looking over on performancetrucks.net and found this:

http://users.adelphia.net/~rhundley/Truck%203-relay.bmp

Hopefully this should help out. It seems like a few other guys had problems with these harnesses as well, but could be user error:

http://www.performancetrucks.net/forums/showthread.php?t=335121&highlight=nelson+harness+diagram

[350SS]

Here's another interesting one about '05 fans:

http://www.performancetrucks.net/forums/showthread.php?t=363110&highlight=nelson+harness+diagram

[Chevy366]

hmm, so the fans from 05 silverado/sierra are better/bigger? whacky, didn't know that. how much are they?
200 from some guy in OK , USA .(will try to find www. address but don't have it at hand)
Yes but requires a 34 inch rad , your's is 27 inch.
Just use the stock 05 fan harness , it will wire directly to your fuse box , nice and neat has all the relays and fuses already installed in harness , 180 from gmpartsdirect , part #15216042 .
And really you should have a 145 amp alt also with either fan type LS1 or 05 .

My truck is a 05 but a HD so did not come with e-fans , but has them now .
05 fans , factory harness #15216042 , and 145 amp Alt .

Sorry guys truck talk .

[DanaliHD]

200 from some guy in OK , USA .
Yes but requires a 34 inch rad , your's is 27 inch.
Just use the stock 05 fan harness , it will wire directly to your fuse box , nice and neat , 180 from gmpartsdirect , part #15216042 .

Sorry guys truck talk .

my truck has the 34" radiator as far as i know because it's a 2500HD. I'll forward this info to the guy who has my truck. thanks again guys.

[ChipsByAl]

To get jump started on what to enter in the "fans" parameter dialog boxes, load a Camaro/Firebird file and view the data. This will give you good ballpark numbers for the a/c control. Most of you will want to lower the coolant enable temperatures.
Al
NOTE: This will not work with the earlier displayed schematic in this thread. You need to use the GM wiring diagram for the 2005 and up dual fan trucks.

[350SS]

Here's the other wiring schematic for dual fan low/high speed control if anyone's interested:

http://img230.imageshack.us/my.php?image=ls1coolingfansbu6.gif

[350SS]

BTW when did GM start using PWM to control fan speed?

[ChipsByAl]

The Trailblazer has the PWM fan control from the start. It does however use a viscous/electronic fan clutch that is belt driven. Some newer vehicles also have a PWM type fan control.
Al