2009 silverado 2500HD electric fan conversion need help

[Glacier]

I am doing an electric fan conversion on my 2009 silverado 2500HD. I am using factory GM dual fans from a 2008 silverado 1500 with a tow package.
I have identified pin 17 and pin 58 for low and high fan control in the ECM. I have a harness from LS1fans.com although I'm not sure I need it.
The fans installed perfectly, the harness works great but I have no fans... they do not come on at all.
if I put either lead, high fan or low fan to ground the fans work perfectly but installed in the harness to the ECM nothing.
Does anyone have experience with what I'm doing on a late model chevrolet, 2007 up?
Does anyone have a screen shot of a file that tells me what to turn on and what settings need to be turned on? The truck does not come with fans stock but seems to have everything on the ECM.
thanks in advance.

[G-old]

I did it on my 07 hd if i remember correctly i only changed number o fans from 0 to 2 and the pwm freq from 0 to 128

[Glacier]

I did it on my 07 hd if i remember correctly i only changed number o fans from 0 to 2 and the pwm freq from 0 to 128

Did you use pins 17 and 58 and did they pull to ground?
I seem to have several fan choices also what did you use?

[G-old]

used original 05+ fans and put relays on the original fuse box where they go on the ones with efans. I had to wire the fans and the low and hi speed fan control, i dont remember which pins they were.

[Glacier]

I have installed both high and low fan relays and fuses. I am currently using an aftermarket fan harness that bypasses all of that. I would love to have this install completely factory. do you know if you can order a factory harness for the fans?
thanks for your help.

[Glacier]

I was able to obtain a wiring diagram from my local dealer now all I need is a screen shot of what to program in the ECM.

[93camaro_zzz]

I just put efans on my 03 2500HD 6.0, and my pins werent the same as yours. Not saying that you are wrong, It's just that we have different PCMs. So with that said, I am sure you have found out which pins were for high fan and low fan. Now, what the PCM does with this, is it creates a ground on those pins. So what you are essentially going to do, is run a power source to the fans, and then run the ground to those certain pins. Of course I used relays on mine, and so in that case the low voltage switch is what you will put to those pins. I made my own "wiring harness" if you will. Not too bad at all.

Then, in the tune, you just put the settings to 2 fans, and enter some values for the on and off temps. Also don't forget to put some values in your idle>airflow table where it says "Cooling fan airflow". You can just put in the stock values from another vehicle.

I would post you a PCM screenshot, but ours will look different. Try what I said above, and see if that is good.

Also, one last thing.... the best way to find out if you even have them wired up correctly, is to command Fans on in VCM controls. If they come on, then you have them wired correctly.

[Glacier]

Yes the fans works perfectly, putting either low or high pin leads to ground.
Yes in the 2007-2010 trucks they use an 80 pin plug and use pins 17 and 58 for low and high relay fan control.
Looks like what I need to do is program the ECM correctly.
Fan type is also required, along with fan qty, freq and the airflow table.

[Glacier]

Screen Shot 2014-02-12 at 3.32.00 PM.pngScreen Shot 2014-02-12 at 3.31.38 PM.png

This is what I think I need to do.

[jetfixrguy]

I know this is a year old but do you happen to have that screen shot you mentioned?

I just put efans on my 03 2500HD 6.0, and my pins werent the same as yours. Not saying that you are wrong, It's just that we have different PCMs. So with that said, I am sure you have found out which pins were for high fan and low fan. Now, what the PCM does with this, is it creates a ground on those pins. So what you are essentially going to do, is run a power source to the fans, and then run the ground to those certain pins. Of course I used relays on mine, and so in that case the low voltage switch is what you will put to those pins. I made my own "wiring harness" if you will. Not too bad at all.

Then, in the tune, you just put the settings to 2 fans, and enter some values for the on and off temps. Also don't forget to put some values in your idle>airflow table where it says "Cooling fan airflow". You can just put in the stock values from another vehicle.

I would post you a PCM screenshot, but ours will look different. Try what I said above, and see if that is good.

Also, one last thing.... the best way to find out if you even have them wired up correctly, is to command Fans on in VCM controls. If they come on, then you have them wired correctly.

[SixSpeed]

Bringing this thread back, there seems to be very little information on swapping to electric fans on the GMT900 trucks since most trucks came with them with the exception of heavy duty gas trucks. I have a 2008 Suburban 2500 that I would like to swap to electric fans. I have done countless GMT800 trucks with various aftermarket harnesses with great results.

I noticed this truck already has relays and fuses in place for fan operation. I was wondering if anyone knew what was required to "finish the job" so to speak and use OEM components for the fan wiring?

Any insight is much appreciated!

[ZforSpeed]

Did you ever figure this out? I'm trying to research how to do this on my 2010 2500hd gas. I'm guessing I need to take pin 17 and 58 and connect them both to the control signal for their respective relays. Then wire up the power to both fans from the hi/lo speed fan relays. Does anyone have a wiring diagram for this? Looking for the exact pin locations to pull these wires to so I can use the stock harness connectors that plug into the back of the relay box.

Bringing this thread back, there seems to be very little information on swapping to electric fans on the GMT900 trucks since most trucks came with them with the exception of heavy duty gas trucks. I have a 2008 Suburban 2500 that I would like to swap to electric fans. I have done countless GMT800 trucks with various aftermarket harnesses with great results.

I noticed this truck already has relays and fuses in place for fan operation. I was wondering if anyone knew what was required to "finish the job" so to speak and use OEM components for the fan wiring?

Any insight is much appreciated!

[[email protected]]

Bringing this thread back, there seems to be very little information on swapping to electric fans on the GMT900 trucks since most trucks came with them with the exception of heavy duty gas trucks. I have a 2008 Suburban 2500 that I would like to swap to electric fans. I have done countless GMT800 trucks with various aftermarket harnesses with great results.

I noticed this truck already has relays and fuses in place for fan operation. I was wondering if anyone knew what was required to "finish the job" so to speak and use OEM components for the fan wiring?

Any insight is much appreciated!

Hello,

First post here and first reply to a very old question. So please if it doesn't benefit you, disregard my response. Anyway guys, I have good news regarding the last two responses prior to mine. I am glad to say that I have successfully added factory cooling fans (including GMT900 complete harness). In other words, my truck is a 2009 SIERRA 2500HD and now it functions a 100% as factory-installed cooling fans that came stock on 1500 truck/suv platforms. This means not only programming, but also all hardware I would say is Original GM including harnesses. If anyone needs specific details on how to figure or successfully execute this, please let me know. I am mechanically and electrically inclined, which helped me do this project all by myself. I live in Saudi Arabia and my area gets super hot so it is needed and it's a good testing ground for this. So far so good, well it is factory quality and installation so nothing new there. I have used the truck since 6 months now with factory cooling fans, factory programming, and factory harness. ZERO issues. If anyone is interested, let me know! I sure haven't found anyone sharing any clear information/write-ups regarding this. I will be happy to assist fellow GM enthusiasts all the way from lovely Saudi Arabia!

Best Regards,
Bader

[Kronstud]

I would greatly appreciate the info on this project, I have a 2009 Chevy 2500hd 6.0 that I would like to do a full EFans conversion on and want to make sure I order all the right stuff and set it up correctly

[[email protected]]

Dear Kronstud,

Sorry for the delayed reply! Stay tuned, I'll post back soon for specific information hoping that you and other members benefit from!

Bader

[Lsx_covi]

Dear Kronstud,

Sorry for the delayed reply! Stay tuned, I'll post back soon for specific information hoping that you and other members benefit from!

Bader

Let me know also i am doing e fan conersion on my 07 nnbs silverado 2500hd gas and i used the oem harness out of a 08 denali. I thought it was just plug it up and tune for the fans i did all that but i still got no fans. At first i had it with a aftermarket harness and a switch but i was tired of turning them off and on every time i turn on and off my truck

[[email protected]]

Let me know also i am doing e fan conersion on my 07 nnbs silverado 2500hd gas and i used the oem harness out of a 08 denali. I thought it was just plug it up and tune for the fans i did all that but i still got no fans. At first i had it with a aftermarket harness and a switch but i was tired of turning them off and on every time i turn on and off my truck

Hey guys, I?m sorry for the late reply. Anyway, here you will find some helpful tips to aid you in building a GM Fan Harness/System. In other words, if you do these steps, you will be having the exact fan setup or configuration that GM built into their 1500 Trucks/SUV?s Platforms. It will also operate 100% the same way (unless altered by you).

Side note: I may have left certain information behind. This may be unintentional as this project includes a lot of information and I have done it since the beginning of the pandemic so my memory may not serve me quite well. Please bear with me or ask anything you are concerned about, hopefully I will answer promptly.

Technical Information:

* This project is intended for the below model vehicles ONLY:
(2007 through 2010) CHEVROLET SILVERADO/GMC SIERRA 2500HD & 3500HD Trucks with the 6.0 liter engine. Diesel engines are not compatible. The ECM?s on the 1500?s vs 2500HD/3500HD gassers are interchangeable. All V8 gasser engines use E38 Engine Control Model. So wiring your 2007 ? 2010 HD Truck?s ECM will be only missing ?two Fan Control Wires? which will be mentioned later on.

* Although 2011 ? 2014 GM Heavy Duty Trucks share the overall design, they are different in a lot of aspects especially the ECM. That is why you may find the information here irrelevant. Maybe it is possible to do, but I haven?t tried so I can?t confirm. They are programmed a little different and their ECM harness is wired differently too so be aware!

Fun Facts!

GM as you know is a Mass-Production Manufacturer so when they design parts, they plan ahead in such a way they cut costs in vehicle production. Why am I telling you this you might ask? Believe it or not, your HD Truck is already wired for Electric Cooling Fans! Well, it almost is, you only need some hardware here and there, and a software program to let your ECM know what have you done to accommodate your hard work 

To explain more, your HD Truck has the exact under hood fuse block as the 1500 Platform except for some factory options that might differ from a truck to another, but that?s not important. What you need to know is that the built-in circuit board is the same no matter what the model is (from my experience at least). So the circuitry are printed from the factory exactly the same for all 2007 ? 2013 (1500 Trucks) vs 2007 ? 2010 (2500HD/3500HD Trucks). Also, did you notice the ?three Fan Control Relays? in your HD Truck under hood fuse block? Yes, that only proves they build them for the HD Trucks too as if they have electric cooling fans. This is how Mass Production Factory works, they have a strategy to build same parts for different models. That?s why I stated that they cut costs as they don?t need to redesign their circuit boards to accommodate only HD Trucks. This is for the consumer?s favor this time lol! Thank you GM for supplying us with the fan control relays including their 40 AMP fuses and the friendly fuse block circuitry.

OK guys, to the important part! I hope at this stage you are not overwhelmed. This was an introduction in an attempt to make the project more understood. This way you will be not only following steps, but also understanding the whole technicality behind it. You can later brag about your accomplishment to your friends 

Now, to the end of the intro; I will conclude that all the reading you just did you must acknowledge the following.
Although GM did most of the work, which is a relief by the way; you should do your part now (coming up)!

* FYI: The Fan Control Relays are already prewired in your fuse block, but missing (Six Wires) connected to them as mentioned below. You will need to remove/lift the under hood fuse block to access the pins and connect the wires accordingly.

1- Ground Input Signal from ECM for Low Speed Cooling Fan Relay Control ?
* (Factory uses Dark Green colored wire).
* Connect to (Under hood X2 Connector Pin A1).
* I have used 18 awg (TXL wire), factory may be same size or 20 awg.

2- Ground Input Signal from ECM for High Speed Cooling Fan Relay Control ?
* (Factory uses Dark Blue with White Stripe colored wire).
* Connect to (Under hood X2 Connector Pin B5).
* I have used 18 awg (TXL wire), factory may be same size or 20 awg.


3- Output to Cooling Fan Motor Supply Voltage ?
* (Factory uses Gray colored wire).
* Connect to (Under hood X1 Connector Pin C1).

4- Output to Cooling Fan Motor Supply Voltage ?
* (Factory uses Yellow colored wire).
* Connect to (Under hood X1 Connector Pin C2).

5- Output to Cooling Fan Motor Supply Voltage ?
* (Factory uses Light Blue colored wire).
* Connect to (Under hood X1 Connector Pin D1).

6- Ground ?
* (Factory uses Black colored wire).
* Connect to (Under hood X1 Connector Pin D2).

Notes:
* It is advised that you locate a 2007 ? 2013 (1500 Series GM Truck/SUV) Factory-Fan Harness to make the job easier instead of figuring out wire lengths, sizes, colors and avoid purchasing them separately. If you go the junkyard route, be mindful that the fan harness is part of the chassis/lights harness. Wires are branched and loomed together. This may be the most time consuming in the whole project from what I remember. Don?t be intimidated, just take your time and separate the loom, tape and branches. Then it?ll slowly begin to reveal the main wires mentioned above. You will notice them easily now that you know their colors. They will be the thickest wires colored GRAY, YELLOW, LIGHT BLUE and BLACK. Please keep in mind that there is a (spliced main ground wire). This is used to feed ground to all the vehicle?s front lighting harness. You will be utilizing it so cut away all the small black wires which are not needed as your truck is already wired correctly. You need only the (Fan?s Main Ground). One end will connect to chassis driver side and one to chassis passenger side almost beneath the radiator core mounts on each side. This is an advantage to you as it?ll make your finished harness almost as a stand-alone harness. For example, if you may decide to service or remove the harness in the future from your truck, it?ll be much easier as it is a bundle for only the fans unlike the truck you removed it from! Just don?t forget to loom and tidy it to make it look like factory.

* Regarding Cooling Fans: You may use whatever you prefer, but for a ?Factory Look?, you may also locate one from the same truck you located the harness if it is available or opt to buy a new one which may get pricey as you need two fans, two fan motors and the fan assembly itself. Do what you prefer as long as it?ll work with the setup. I would like to bring to your attention that GM Cooling Fans came in several configurations such as 5/7 blades, 7/9 blades. All should work but my advise is to purchase a fan that?s designed for 2007 ? 2013 generation 1500 Series Trucks to be in the safe side as the older ones may differ slightly.

The ECM!

Wiring the ECM is easy as adding two wires. NOTE THAT THESE TWO WIRES ARE THE SAME ONES MENTIONED ABOVE UNDER ?Ground Input Signal from ECM for Low Speed Cooling Fan Relay Control? & ?Ground Input Signal from ECM for High Speed Cooling Fan Relay Control?, but this time it is explained from the ECM?s side of things. So now we?re speaking of the Ground Output Signal that starts from the ECM to the Under hood X2 Connector that has already been covered previously. The two wires coming from X2 Connector should be connected as follows.

1- Ground Output Signal for Low Speed Cooling Fan Relay Control ?
* Same Dark Green colored wire that should be/will be connected to Under hood X2 Connector Pin A1.
* Connect to (ECM Connector Pin 58).

2- Ground Output Signal for High Speed Cooling Fan Relay Control ?
* Same Dark Blue with White Stripe colored wire that should be/will be connected to Under hood X2 Connector Pin B5.
* Connect to (ECM Connector Pin 17).

You?re almost there!

The hardware work is considered done; assuming you already installed your cooling fans and so on. By the way, I think the fan connectors are called (GT Connectors). If you bought from a junkyard or new, you should be able to connect them with no issues as long as the hardware came from or bought for a 2007 through 2013 (1500 Series Truck).

Programming Your ECM

This is the fun part! You may use a software program of your choice such as EFILive. I personally have used HPTuners.

Note: For further details on how to setup (tune) your E38 ECM, let me know here. I may screenshot what is needed. I have not done it already as the information is available across the Internet. Despite that, I will assist anyone who needs any help.

Sorry, I haven?t added any pictures to support the information above and I may have left some details, but I assure you if you understand what you?re doing, this will definitely help you out!

[Jayj84]

Thanks for all the info and the great write up. I'm getting ready to do this in my 07.5 Silverado 2500hd. I have the fans and the tuner turned them on for me when he did my initial tune. Sounds like I need to find a factory fan harness now. Thanks

[[email protected]]

Hi there,

Well good luck! I?m sure you?ll enjoy the outcome especially knowing that the installation is factory. Hopefully zero issue, it?s very reliable and simple circuitry from GM!

Also if for any reason in the future you face any problems in the cooling fans department, it?ll be very easy to diagnose and pinpoint the main issue.

Bader