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  1. #1

    Default flexalite fan installation

    Hi all, I finally installed my flexalite electric fan and it works great! The first time I test drove it I immediately noticed an increase in HP and throttle response. It was fairly easy to install, the hardest part was trying to figure out how to remove the stock radiator fan. If anyone is wondering how you do this on 1999-06 GM trucks, you have to get a strap wrench to hold the water pump pulley from spinning and get a wrench to loosen the fan/clutch nut. As for the wiring, it was easy considering I'm not very experienced with electrical work. The kit comes with detailed instructions so it's dummy proof. Just figured I'd share my thoughts with everyone on the installation. If anyone has any questions, please feel free.

  2. #2


    I did the same kit on my 2004, I love it. Despite the price tag :P I originally installed the flex-a-lite fans when my truck had a v6, and the gains weren't really noticeable.

    But now that my truck has a built up SBC, the flex-a-lite efans are able to keep that monster cool, even with the v6 radiator.

    The fans are loud though, especially with the 30 sec run on time after the engines off... people look at my truck like a harrier jet just landed. lol

    cheers ~Mykk

    Vortec 357ci Small Block Chevy: Big cam, high stall, long headers, rear gears. The typical formula.

  3. #3

    Default TO: 04Silveradomykk

    Hey, I think I have a problem, so I understand that the fan running for 30 sec. after the engine is off is normal... is it normal for it to continue working after that? The #4 LED is lit even with the engine off. And could this pose any problems with drawing amperage from the starter when you startup?
    2001 Silverado Z71, 5.3L, K&N cold air intake, flexalite electric cooling fan, Edelbrock shorty headers, Amsoil synthetic oil, dual exhaust flow master 40 series muffler, Hypertech max energy programmer, MSD Ignition plug wires.

  4. #4


    As long as you have them wired correctly there shouldn't be a problem.

    On the VSC controller:
    Thick black battery ground
    thick red battery positive
    terminall #9 is a switched +12v
    terminal 7 or 8 A/C compressor input (+ or - will decide which terminal)

    The only reason I could think that the VSC controller would stay on is if terminal #9 isn't on a switched +12v

    And I hope you wired directly to the battery, those fans can have a massive peak/spike of 50 amps draw when they first kick on.

  5. #5


    I figured it out...the fuse that I tapped into was hot even with the ignition off so the VSC thought the truck was still on. It took me a while to find a fuse that was only hot when the ignition was on but now it works like a dream. Thanks.

  6. #6
    Legend bry2500's Avatar
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    Oct 2008
    Gloucester, MA
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    Is there a noticeable difference in HP gains? Can you tracck and MPG differences for us. I am considering these but have been told that for my 8.1L they don't work well and burn out the alt, because they draw so much amps.


    02' Avalanche 2500 Onyx Black
    8.1L Vortec
    43,000 miles

  7. #7


    I did in fact notice an increase in HP, as for how much more and how many MPG's I gained I don't know. Removing your engine driven radiator fan takes a substantial load off your engine. When I ripped out the fan on my 5.3L I was surprised at how heavy the fan/clutch assembly was. I haven't heard about the fan burning up the alternator, I don't think it would be a problem. If you do get one, when you get to the wiring portion... you have to tap into a fuse that's hot only when the ignition is on. if you tap into a fuse that's hot all the time like parking lamps or cigarette lighter or something the fan will think the engine is running and will keep operating even when the engine is off and it's hot enough. So if you're looking for more HP the fan is a good way to go. Get a Flexalite fan.

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