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Installing Electric Fans


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I want to replace the clutch fan on my 2003 silverado 1500 Z71 with a pair of electric fans. Has anyone done this switch before? Is it easier to buy the fans from a dealer or new somewhere, or to go to a local junk yard and get some off a truck like mine? The other thing is, after removing the fan shroud on my truck, will the new electric fans just bolt in or do I need some type of a bracket or different sized radiator?

 

The next thing, how hard is the wiring? Do the fans need to be hooked in to a relay or have a fuse or anything? Where do I splice into for power to the fans? And does the trucks computer need to be adjusted to kick the fans on at a certain temperature? Sorry for all the questions, but just have one more. Will I need a higher output alternator to power the fans? The alternator on the truck now is a 105 amp. Will I need to go up to 145amp?

 

If anyone has any info on this, please fill me in on everything I need to know. If there is a previous thread on this somewhere or on a different site, feel free to post a link as I am really wanting to do this swap but I have no idea where to start. Part numbers for anything I should need are also appreciated. Thanks guys!

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Here is a link to a wiring harness for the PCM to control the fan(s).

 

Wiring Harness for Fans

 

 

As far as the fans go, a salvage yard is the cheapest but you can also buy them from Flexalite

 

 

Thanks for the link. Is installing the harness pretty straight forward? Will the PCM still need to be tuned to turn the fans on at a certain temp or does this harness take care of that for me? Also, what is an alternator overdrive pulley? Is this necessary when installing electric fans? Thanks

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  • 4 weeks later...
Here is a link to a wiring harness for the PCM to control the fan(s).

 

Wiring Harness for Fans

 

 

As far as the fans go, a salvage yard is the cheapest but you can also buy them from Flexalite

 

 

Thanks for the link. Is installing the harness pretty straight forward? Will the PCM still need to be tuned to turn the fans on at a certain temp or does this harness take care of that for me? Also, what is an alternator overdrive pulley? Is this necessary when installing electric fans? Thanks

 

 

I did this mod on my 02 Silverado HD. The harness is super easy. Good picture directions supplied too. Justin at BB Perf tuned my truck and as part of the tune, he turned on the ability to run elec fans in the PCM. That was because no 02s ever came with elec fans. I used his wiring harness (link in previous posts). Justin also gave me a link to a guy on ebay who sells the OEM replacement fans brand new and at a good price (about $250 I think). I'll look for the seller in a min. The greatest part was how easy they dropped right in. Once the fan shrouds and fan are removed, all the alignment tabs, notches, retaining lips are all exposed and my generic eBay fans dropped right in and two holes at the top corners align perfectly with the 10mm bolt holes used at the top of the shrouds. Piece of cake. The fans even have holes for wire loom clips and ring holders to clamp down the wiring harness in all the stock places. I bought the clamp-rings at the local AP store fore a couple dollars. Just email Justin at bb perf to ask about turning on the function in the PCM. His wiring harness may take care of that step itself on your year of truck. OK the email for the seller on ebay where I bought my elec fans is [email protected]. I think his ebay seller name is just xtremelights2003 or xtremelights. If it helps, Justin told me to buy the ones advertised for a 2003 Tahoe and they fit fine. Good luck.

Jim

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  • 2 years later...

I was going to do this to my 02 1500. Instead, I just got an 05 1500 crew cab that has the factory e-fans. In our heat, it sooo much nicer not to listen to that bus fan roaring away under the hood as I am running around town. My 95 Impala SS had them and I really liked the noise level (or lack of). I auto-crossed the SS in the summers and never had an issue. I think it is a good mod to do.

Good luck. Do a search and there is a ton of info out there about this, some include pictures and parts list.

 

Babyhauler

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  • 1 year later...

My biggest question is why? If your thinking more HP then the answer is no gain.

 

 

Why do people always say that you don't gain any horse power by adding an electric fan?

(because the load is more on the alternator) WHATEVER!!!

 

1HP = 745.7 watts

30 amps at 12 vols = 360 watts.

 

So... It takes approximately a 1/2 a horse power to run your typical 30 amp duel electric fan. (which most are that or actually less)

 

Further more... When you are heading down the road, Your electric fan shouldn't have to runat all. You should get enough air through your radiator to keep your engine cool. Fans are normally for when sitting at a stop and there is no air movement going through your radiator.

 

Now I'm not saying you will gain 15HP or even 10HP. It may only be 5HP or it may be 30HP, but can we please quit saying you don't gain any horse power at all! It's obvious you gain something!!! Is it worth the money? That's the real question! lolol

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I just did the switch a few months ago. Also to the gain hp argument... you dont gain any, you free up some of the existing that was killed by the clutch fan

 

Sent from my Samsung Galaxy S4 using Tapatalk 4

 

 

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Nice thread dig lol. I have posted about this multiple times myself... every one of my trucks in my signature have e fans on them. I use the dorman replacement OEM fans ( 2005-2013 all interchange) and the OEM harness from the 05 to 07 classic trucks. Works well.... and I mean works OEM because with the 03 up pcm it hooks up as per factory.

 

That gain to me was silence.... a/c working immensely better at slow speeds and the biggest being the warm up and temperature holding ability in the winter. Viscous clutch fans are complete garbage in freezing temperatures.

 

Sent from my SGH-I747M using Tapatalk

Edited by Notamember
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I just did the switch a few months ago. Also to the gain hp argument... you dont gain any, you free up some of the existing that was killed by the clutch fan

 

 

Duh... That's the whole point, freeing up HP... Does it give you more HP in your engine? No, but does it give you more HP to the ground yes... So you are gaining Horse Power... Freeing up Horse Power "is" gaining Horse Power!!! (Common Sense)

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Nice thread dig lol. I have posted about this multiple times myself... every one of my trucks in my signature have e fans on them. I use the dorman replacement OEM fans ( 2005-2013 all interchange) and the OEM harness from the 05 to 07 classic trucks. Works well.... and I mean works OEM because with the 03 up pcm it hooks up as per factory.

 

That gain to me was silence.... a/c working immensely better at slow speeds and the biggest being the warm up and temperature holding ability in the winter. Viscous clutch fans are complete garbage in freezing temperatures.

 

Sent from my SGH-I747M using Tapatalk

 

 

I agree... I was just thinking about that yesterday when I acidently left my truck out all night. I got in it and it was cold... Although it does however warm up fairly quickly, but it should warm up much quicker with an electric fan installed.

Winter is around the corner... I'm hoping to have my fans installed tomorrow or the next day. (my weekend)

 

 

If it turns out well I will be posting pictures and more about how it was done and how it's working out. Mine is not going to be your typical swap. I got my duel fans out of a junk yard. ($30) They are each 14" fans (total or 28") (stock is 18")

Last week I took the mechanical fan and shroud off for fitment, So far it's only been 3 small minor cuts for more clearance for the upper radiator hose, and a couple for better fitment. (grinding with a drilmel) Bought a relay and a fuse from Advance auto, ($10) Been doing research online for a few weeks to make sure I hook everything up correctly. If it all goes well (which rarely does) it should be a great $40 swap. (I know sounds too good to be true) If it works, it will be worth the money.

 

My only real question is... Will my stock ECT sensor work as the termostat for my electric fan and relay?

I've been told it will but I have my doubts.

 

P.S. Don't go buy the fan removal tool. Just get a wrench or even a pipe wrench and tap it with a hammer. I heard that worked great... I did it, and it came off just like it was supose to. Really Easy!!!

Edited by SteveLNew
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I dont know what year your truck is but if its 03 up you reference the pcm via pin 42 on the blue connector it can ground a relay as that is all it does with the stock arrangement. You have no a/c(defrost) system control though either way, just engine temp. Even 99 to 02 is the same deal but those don't have the a/c control anyway.

 

You need the pcm tuned though to activate the pins and set values for on and off though. Its not enabled as the truck sits.

 

Fan removal is simple. I don't tap or anything. I have big wrenches and I think its 1 3/8" that fits. Hold the water pump with a makita grinder disc tool and off it comes... no matter how seized up it is.

 

Sent from my SGH-I747M using Tapatalk

Edited by Notamember
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