Electric fan conversion for 2004 GMC Sierra 1500 (5.3L)

Discussion in 'GM Electrical Tech' started by SurrealOne, Jun 15, 2012.

  1. SurrealOne

    SurrealOne Former Member

    Does anyone have experience with electric fan conversions? I have an engine-driven fan in my 04 GMC Sierra 1500 and am curious what it'd take to convert to an electric fan setup. I understand the 05 and later came stock with one, so I'd think I should be able to convert to one easily enough ... gaining some ponies back and, hopefully, cooling the engine a little better. I've already got an upgraded electrical system, so an extra 30-40 amp draw is no problem...
  2. Crawdaddy

    Crawdaddy Moderator

    I think for your year truck, a reflashing of the computer will allow you to use an output pin of the computer to control the e-fan turning on and off. You'll still need a high-amp relay to do the heavy lifting, but you won't need any additional temp switches or anything.
  3. rileyjr16

    rileyjr16 New Member

    My brother put 2 universal fans on his 99 4.3 and a aftermarket harness and relay and I might do the same but I'd try and hide the wires best I can or wrap them with that split flex tubing stuff. I hate looking at wires and they just get in my way...:grrrrrr:
  4. SurrealOne

    SurrealOne Former Member

    What's he using to control the temp at which the fans come on/off and where is that temp control plugged into (radiator presumably?) The wiring's a non-issue and I have piles of 3/8" wire loom (the name for what you called the 'split flex tubing stuff', lol).



    Reflashing to what {flash version} and by whom {the stealership}?
  5. reggiecab2000

    reggiecab2000 Member

    im planning on doing the same by summers end and have found many how-to's all over the internet from LS1's to ford taurus swaps...
    personally i am going to go the LS1 route (2 fans) as opposed to the ford taurus route (1 fan, 2 speeds)... i will hopefully be starting it in the next month...
  6. SurrealOne

    SurrealOne Former Member

    Any chance you might do a guide in the process ... or link a guide you've found to work well?
  7. rileyjr16

    rileyjr16 New Member

    Yeah [MENTION=50075]SurrealOne[/MENTION] the temp sensor is just plugged into the radiator I belive.
  8. Sierraowner5.3

    Sierraowner5.3 New Member

    @surreal, you may be able to find a wrecked 05 + and take a look at whats different between those and yours. most everything should just bolt right up. My buddy that has a 99 silverado was looking at doing the same thing. I loved the electric fans in my 05, gave you more room to work and more clearance to check the serpentine belt and so on. I also thought they were quiter the the engine driven fan.

    Alex
  9. reggiecab2000

    reggiecab2000 Member

    If the install goes great, i might try to do a guide, but if for some reason i cant i do have a few links for you to check out, although most deal with silverados, but sierra should be the same foundation...
    http://www.fullsizechevy.com/forum/general-discussion/performance/475723-electric-fan-swap.html

    well i though i had about 2 or 3... anyway google is definitely your best friend here :)
    but from everything i have seen this install seems to be about a 4 out of 10 difficulty rating!
  10. Crawdaddy

    Crawdaddy Moderator

    I'm not sure what version the software in the computer has to be, but I know there are boatloads of companies out there that can do it. You definitely don't have to go to the dealership and I don't think they'd help you anyway. There may even be a handheld tuner that can do it, but I haven't researched it alot as I don't have a truck I can do that to.

    I am planning on doing the Mark VIII fan conversion. It's very similar to the Taurus fan swap except I think it moves a couple CFM more air through it. It's one HUGE fan. When I do the install I'll be taking pics the whole way. I'm going to have to go with a fan controller for mine and figure out where I should put the temp probe.
  11. SurrealOne

    SurrealOne Former Member

    Tomorrow morning I'm picking up an OEM radiator, efan harness, and efans from a 2005 Silverado. While researching, this week, I learned that pins 33 and 42 are what are used in the 2005's and that they can be enabled via a custom tune from the likes of Blackbear, Diablew, etc. Since I already have a Diablew tune I've reached out to Lew to get the efans turned on in a new tune revision for my truck ... and set to: fan 1 off - 189; fan 1 on - 196; fan 2 off - 197; fan 2 on - 205. (I believe these are the stock settings.) This will let the computer control the fans and should preclude the need for a temperature probe.; I'll simply have to wire into the truck via the OEM harness or, if it turns out to be toast, procure a Blackbear or Nelson Performance harness. :)

    @Crawdaddy, any chance you could provide insight as to the clutch fan removal? I've read about the need for a special tool to do it ... and know it can be obtained on loan from Autozone and the like (a refundable deposit is all that's needed). However, I've also read that it can be done with no special tools, using a BFW and BFH. Since you're currently ahead of me on an efan conversion if you can take some notes on how you did/do the clutch fan removal it'd be appreciated!
    Last edited: Jul 17, 2012
  12. Crawdaddy

    Crawdaddy Moderator

    For me, the clutch fan removal is stupid-simple: remove 4 nuts off the water pump pulley studs, and remove the whole assembly. For those who have the big honkin' nut that holds the clutch fan on, a strap wrench on the pulley the fan's hooked to a strong friend, and a wrench with possible a hammer should handle it.
  13. SurrealOne

    SurrealOne Former Member

    Thanks, [MENTION=14098]Crawdaddy[/MENTION]. I've got a strap wrench, a BFW, a BFH, and a strong friend, so I'll avoid the loan-a-tool bit and give it a try when I'm set. It'll be a while before I'm ready to do the conversion as I've got a number of irons in the mod fire, already ... and need to complete those projects first. I'll probably photodocument for good measure...

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