Has anyone thought of putting in a new fan from the 05 lade in thier 02-04 model....looks like it would be a pretty easy mod...would only have an issue of getting it to activate via a thermostatic sensor, im pretty sure the pcm controlls the 05 models..

one would also need a hi(er) amp alternator..

May be worth a bit more fuel milage/performance....anyone?

I would say that the benefit would be minimial at best. Barely noticeable.

It will actually have a pretty good increase in power and gas mileage not to mention they are much quieter most of the time. They add approx. 15hp and 1-2 mpg city. GMC re-rated the Denali for '05 from 320hp to 335hp the only difference being the efans. It costs a great deal for a company to go through the EPA process to re-rate a drivetrain, that is why it was not done by the other divisions with a new drivetrain coming next year. So logical guesses would have that the rest of the 1500 trucks are underrated by about 15hp.

The fan part is easy, but the radiator is larger. You will need a new radiator, efans, wiring and someone who can turn on the signal from the computer (it is built into the ECM). Alot of guys go for the camaro efans from junkyards (usually $75) instead of the truck fans- I would prefer the truck fans. The LS1tech forum has dozens of threads on this.

Has anyone thought of putting in a new fan from the 05 lade in thier 02-04 model....looks like it would be a pretty easy mod...would only have an issue of getting it to activate via a thermostatic sensor, im pretty sure the pcm controlls the 05 models..

one would also need a hi(er) amp alternator..

May be worth a bit more fuel milage/performance....anyone?

I dont think it would be that easy to make it ourselves, not without proper knowledge and tools...

However my 05 EXT feels quicker than my 03.......

At least 15hp will be gained...

Just my $.02

Mejia

Im sure someone has to have the aftermarket setup like they do for the earlier c/k chevy's...without going throught the whole trouble of pcm modificaton, larger radiator ect ect..

Yes you could go the flex-a-lite route. They are expensive and loud, but work. I'd prefer the stock ones that GM designed for the truck. The radiator is easy to swap out and I would trust the PCM far more than some aftermarket trigger box (biggest reliability problem with flex-a-lites). All you need is a tech II or Hptuners and it is one quick on/off screen. The cheap route is the camaro fans, no radiator change 75 bucks and a relay plus maybe $30-40 for the dealer to turn them on.

Yes you could go the flex-a-lite route. They are expensive and loud, but work. I'd prefer the stock ones that GM designed for the truck. The radiator is easy to swap out and I would trust the PCM far more than some aftermarket trigger box (biggest reliability problem with flex-a-lites). All you need is a tech II or Hptuners and it is one quick on/off screen. The cheap route is the camaro fans, no radiator change 75 bucks and a relay plus maybe $30-40 for the dealer to turn them on.

So where is the lead wire for the fan located...as you said to turn them on

In the ECM harness. It is an empty bay that needs to be tapped, I don't remember the exact location, I had installed one last year, but I'm sure someone with a manual can chime in. You also need to tap the compressor wire for the A/C.

Edit- here is a link to a thread that would help:
http://www.ls1tech.com/forums/showthread.php?t=233326&highlight=efans+pcm+wire
Nelson now makes a great harness that would do the job.

Ed