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Thread: PLEASE help w/ e-fan conversion settings...

  1. #1

    PLEASE help w/ e-fan conversion settings...

    Good day everyone. I'm brand new here, but have a little experience with tuning, but have a problem my tuner can't seem to figure out, and I've literally searched since the beginning of the month, here, and across the internets with no success. HP' has also told me, as I've noticed, that they don't tune, and directed me to the Forums for assistance. I'll try to be brief, and cross my fingers for the generosity of this great Community.

    So - the vehicle is an 05 Hummer H2. It has automatic temperature control, and I completed an electric fan conversion a while ago (there is a back story that I don't think is important, that I can elaborate on if anyone believes it's important). Over the summer, I finally purchased a Nelson Performance (3-relay in case there were any questions) conversion harness and thought the PCM had the necessary pin(s) activated. It's my understanding that it is Pin #42, specifically, that has to be. The harness as the PCM terminal, in addition, it has the Pin #33 terminal, too, which I double checked connections on last night. I've also purchase a couple files from truck with e-fans, and tried to find differences, without too much success - BUT - I did find one which is part of my question...

    So, I have the fan settings, under Fan Type, set to 2 Fans. I've adjusted both fans to come on around 190* with and without the A/C on. Under Recirc Option, I have selected Fan #2 and have A/C Type Fitted as Serial Cycling.

    What I'm finding is both fans ALWAYS run on high, regardless if the engine is dead cold from sitting overnight, and whether or not the A/C is running. The low-speed NEVER activates. Why is this? I've tried changing Recirc Option to AC Auto and the fans will ALWAYS run on low, regardless of engine coolant temperature and if the A/C is running or not. It will NOT ever engage in high-speed. I have also tried all the other options in A/C Type Fitted with no change in operation - they always run in low, regardless of any other condition.

    What gives?... The one table I think I see a difference is under Engine, Idle, and Airflow tabs. I see there was a table where the values were different than mine (referring to an '06 6.0 Silverado tune that I bought) but I'm not sure if the control the actual fan speed or not, or if I'm completely off. I'm hoping someone here might have an answer; maybe give me an idea if there are values I can use to reduce the speed of my fans, while at idle, when they aren't necessarily needed to cool the engine because it's not hot and if the A/C isn't on. Again - they just run on HIGH all the time right now, and it just isn't right.

    Any help would be appreciated like you wouldn't know. Thank you very much and have a great day.

    Attachment 48545Attachment 48546

  2. #2
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    The green control wire should go to the Blue connector pin 42. The blue control wire should go to the Green connector pin 33. I would start by testing the harness independent of the PCM. Disconnect the control wires from the PCM connectors. Manually apply a ground to the green wire. Both fans should run low speed. While keeping that ground applied apply a ground to the blue wire. Both fans should run high speed. Only after you verify proper fan operation that way should you look at the PCM programming. The auto recirc option only comes into play when adding e-fans to a 99-02 truck. Do not select that for your vehicle.

  3. #3
    Ok. I'll go back and check into that. I will make sure to NOT use the auto recirc option for my vehicle at all.

    Thank you SO VERY MUCH!!!

  4. #4
    Alrighty - I don't mean to sound like a smart arse, so I'm sorry if I do, but I checked the harness, after checking with Nelson, and after pulling the PCM connections, and grounding the blue wire, I get both fans to run on low. After I ground BOTH the green AND blue wires, I get BOTH fans to run on HIGH. This is how Nelson said it should perform...

    Would anyone be generous enough to give me advice where to go to next?

    Thanks VERY much.

    Chuck

  5. #5
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    When I told you to ground green for low speed fans and both green and blue for high speed fans I was going by the colors used in a factory harness. Even the few after market harnesses I've seen use that same color coding for their control wires. If Nelson's harness is opposite then he is not building his harnesses like the others I've seen and conforming to the factory colors. Not surprising from Nelson. Here is a SD of the typical fan wiring used on 05-07 classic trucks.

    E_Fans_Big.JPG

  6. #6
    AH. I believe I see what you mean. Yeah - I'm not sure as to why they are built this. For me, matching the blue and green terminal covers (on the harness connections) to the wires seemed like it made sense, but I'm not sure it that was the intent...

    Are there any other ideas on why I can't get these things to operate at low speed?...

    Thanks VERY much, and I hope everyone has a GREAT day!
    Chuck

  7. #7
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    Have you tried commanding them on with the scanner bi-directional controls? If they work manually grounding the control wires then double check your wiring. In the file you posted auto air recirc is enabled. Set that to fan 2. State again which color wire you have going to what connector terminal.

  8. #8
    I have not tried that yet. I have noticed others commenting that they've done it, but I haven't figured out how exactly to control them... If you could direct me to where I can figure that out, I surely will give it a shot and test. I can manually turn them on, the way Nelson says they should (according to the way they say it should), by physically grounding the PCM terminals (I added from their kit), to the battery ground (inserted a pick into the terminals, and clean used a clip to ground the pick to the negative battery terminal). I did have the AAC selected in that file, and have it switched to Fan #2 now, but I still get only high-speed from both fans, any time, all the time, from as soon as I start the vehicle, until I shut the engine off. Right now, I have the blue wire connected in the blue connector cover to Pin #42 and the green wire connected in the green connector cover to Pin #33. Here is the link for the instructions http://www.nelsonperformance.com/fan...s-instructions in case I screwed that up (I tried attaching the instructions but I got an error saying I couldn't, and I can't post the exact link, but I am using the '03-'04 harness and instructions...). I have everything connected exactly as the instructions say, and the fans, when I ground them manually, operate exactly the way Nelson says they should, they way they said to ground them.

    I'm sorry for all the fuss, but THANK YOU VERY MUCH FOR YOUR HELP

  9. #9
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    At this point if you are absolutely sure you have the control wires in the correct locations I would load a 05 Silv 5.3L stock file (came with e-fans) as a compare file and copy over all the fan settings to your file. Here is a 05 Silv 5.3L stock file with the same OS as your Hummer file. As far using the scanner to test them, with KOEO, connect the scanner. Click the VCM Controls icon and then the Fans tab. You can command fan 1 and 2 on and off with the buttons.

    2005Sillv53A4.hpt

  10. #10
    THANK YOU SO MUCH!!! I'll get to work comparing and copying differences. I'll also try to test with the scanner like you described.

    Again - thank you VERY much.

    Chuck