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 ROTM Winner 1000 Posts

    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
  2. Crawdaddy

    Crawdaddy All hail the Mad King!! Staff Member 5+ Years 1000 Posts Platinum Contributor

    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.
  3. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    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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