Could you guys help me figure this out. I have a friend that's tradeing in his 05 gmc truck with the efans. I have and 04 silverado without the efans. I was wondering he said i could take his fans before he traded his truck in. MY questions is will his efans fit my truck? If so what will i need to do to put my fan work on his truck and then make his fans fit my truck please let me know. He plans on tradeing his truck in this week.

 

That is a great way to get 05 fans.
Here is what you need to do, err. what I did....
First thing is first you need the big radiator, 32-34" I can't remeber.... Do you have the big one or the 28"?

Assuming you have 34" rad..
Pull the fans. carfully unwrap the wiring harnness from the fans, this will take a bit of time. there will be a two pin plug that comes off the harness and goes to the PCM. You can just un-clip the connector, or better yet pull the pigtail from the PCM with the two pins... (note pin location)
There will be a ground wire that goes under the right marker, it will be a pita. so you might just want to cut it and add a new grounding eye to the wire. all the other wiring will go to the left towards the pcm, there is other wires ran in the same loom as the fan harness, fyi...
Remove the left rear fender support that covers up the corner of the fuse box under the hood. Pull the lid off the fuse box, then pull the box off the mounts. You will want to swap the lids *** well, because the e-fan relay lid that is cut out. Remove the single bolt holding the relay block down, along with some other crap if I remeber right. You also might need to pull the main fuse block up enough to get the harness going to the relays out for underneath.....

So, to recap.
You will need,
Fans
Relay block
Black fuse cover assy.
possable a 34" rad
pig tail from pcm to fan harness. (two wires)

I hate to tell you this, but it will set a code in your buddys truck, if the fan relays are pulled. I think.........

 

since the fans are made for the 05 trucks do the water pumps even have a threaded portion for a clutch fan? Dont quote me but i think the 34" radiator is a requirement. Just save you and him alot of trouble and get some f-body fans and a harness from nelson or whoever you prefer---(god forbid i start naming favorites on here)

 

I'm pretty sure that the 05's do have the threaded portion for the clutch fan, but you'll have to look at that. Yes the 05's require a 34" radiator, but if he's willing to let you do the swap, then you can swap out the whole she-bang. Give him your radiator, shroud, and clutch fan, and take his radiator and fans, and get yourself a Nelson harness and have your PCM tuned to turn em on. Just hide his old fan harness (tuck it down under the fan shroud), and you should be good to go. Not sure if deleting his fans/ leaving them un-plugged will cause a code, hopefully someone will chime in with some info on that. His truck should cool fine with your set-up on it...that's what they used for 6 years leading up to 05

 

The water pumps are threaded.
I know I have put a 05 ecm in a 04 and got a e-fan code........