Questions about adding factory e-fans to my 04 silverado

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05-04-2009, 04:02 PM

#21

RWC

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Quote:

Originally Posted by Dark Halo

just wondering if I run a wire from the one tied into pin 33 and then to my switched ground will this allow me to turn the fans on high speed?
sorry for being off topic just really wanted to know this

Pin 33 (hi) and 42 (lo) are both "switched to ground" by the PCM to activate. Just make sure that the PCM pins are hooked to the "ground" leg of the relay circuits, not 12V. Hope this helps.

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05-04-2009, 11:13 PM

#22

neilownz

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Yikes $160-200 for that harness.

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05-05-2009, 11:26 AM

#23

therock

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Incase cash for factory fans is too much I have a set of Flex-a-lite 282 fans for the 34" radiator. No controler. 150.00 +shipping. GM Classifieds.

Very little time on them.

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05-06-2009, 12:35 PM

#24

Dark Halo

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Quote:

Originally Posted by RWC

Pin 33 (hi) and 42 (lo) are both "switched to ground" by the PCM to activate. Just make sure that the PCM pins are hooked to the "ground" leg of the relay circuits, not 12V. Hope this helps.

is this all years or 05 and up. My fans are on a 02 so just wondering if the pin is the same

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05-06-2009, 10:23 PM

#25

budhayes3

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Quote:

Originally Posted by Dark Halo

is this all years or 05 and up. My fans are on a 02 so just wondering if the pin is the same

I believe that for an 02 you use the same pins of the PCM. Pin 33 has something to do with auto recirculate or something...there's a thread floating around that references it in the General Section I believe.

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05-06-2009, 11:44 PM

#26

neilownz

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I'm pretty sure you have to use the "aux fans" and not the "2 fans" setting for the older pcm. I should be getting my nelson harness monday and messing around with efans the weekend after.

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05-07-2009, 12:21 PM

#27

2000Silvy

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Quote:

Originally Posted by budhayes3

From what I remember when I did my 05 efans, the radiators looked the same except for the cores....but that was a few years ago. You won't have to drill and tap for the fans, they slide right in. You'll just need 2 more bolts for the upper fan mounts...if you want to be really **** you can get them from the dealer so it looks totally stock

You'll have to trim the 2 rubber flaps on both sides of the radiator with a razor blade or even scissors since the 34" rad is wider (no biggie, you don't even see them), and get or make a harness. I have the Nelson harness and it's been flawless for me for about 4 years-ish now. Then tune the PCM to turn them on and off at your desired temps.

My 05 fans....(I used aftermarket bolts to secure mine...I'm kinda **** myself so it bothers me a bit, I may swap them out some day...)

Did you get a higher amp alternator too?

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05-07-2009, 11:14 PM

#28

budhayes3

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Quote:

Originally Posted by 2000Silvy

Did you get a higher amp alternator too?

I did, but from what I've seen it's not necessary. tdrumm did the same fans/radiator combo and didn't upgrade the alt, he was still rockin the stock 105 amp right up to the day he traded in the truck...

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