I installed E-fans on my 2001

[Rocket Man]

I have the OEM harness I have a 01 thi and it needs the extra relay

Oh THAT relay. Bosch is great quality.

 

[ieastsidechevyrider]

I highly recommend an OEM harness from a junkyard or even better, @ScottyBoy gets them, cleans and fixes them up and sells them. If he doesn’t chime in here, send him a private message. I went through 2 complete aftermarket harnesses and they kept melting. Once I was left stranded 100 miles from home in 100 degree heat because my truck overheated due to no fans and a melted relay pack. Since installing an OEM one, no issues at all.

Which aftermarket harnesses did you have? i have one from JustChevyTrucks, and I have had nothing but problems with it.

 

[Rocket Man]

Which aftermarket harnesses did you have? i have one from JustChevyTrucks, and I have had nothing but problems with it.

I had one from www.ls1fans.com and it melted, left me stranded 100 miles from home in 100 degree temps. I rebuilt it completely with heavier wiring and heavier relays and relay blocks but it started melting both the 60 amp mega-fuse holders I upgraded to. The OEM harness has had no such issues.

 

[ieastsidechevyrider]

I had one from www.ls1fans.com and it melted, left me stranded 100 miles from home in 100 degree temps. I rebuilt it completely with heavier wiring and heavier relays and relay blocks but it started melting both the 60 amp mega-fuse holders I upgraded to. The OEM harness has had no such issues.

i think I may have to go the OEM route, then...

 

[UmmScott]

Yeah...that write up about using AC pressure is overly complicated and in my opinion could be gone about a much simpler way.

Just use a pressure Switch, not a transducer. Wire it in series with the wire feeding the relay coil that gets activated with the AC signal.
Fan stays off when ac comes on...high side pressure rises...fan comes on.
Fan stays on till either ac is shut off or till high side pressure drops. (I'd find a switch that closes at 250psi and opens at 200. Seems ideal for automotive)

AND... for you guys that want the fan to shut off when driving down the road this will do that!.
It will eventually shut off at highway speeds and stay off till u get back to stop and go traffic.

No need to mess with more PCM configuration.
A simple switch gets it done

Sent from my SM-G975U using Tapatalk

 

[ieastsidechevyrider]

I had one from www.ls1fans.com and it melted, left me stranded 100 miles from home in 100 degree temps. I rebuilt it completely with heavier wiring and heavier relays and relay blocks but it started melting both the 60 amp mega-fuse holders I upgraded to. The OEM harness has had no such issues.

I can confirm that the OEM harness is the way to go! Have not had any more issues. Got one that I pulled from an Avalanche for $20. Wish I had done this in the beginning instead of paying $160 for the BS harness from Just Chevy Trucks.

 

[Tonyrodz]

I can confirm that the OEM harness is the way to go! Have not had any more issues. Got one that I pulled from an Avalanche for $20. Wish I had done this in the beginning instead of paying $160 for the BS harness from Just Chevy Trucks.

Don't they just deal with used oem parts?

 

[Rocket Man]

I can confirm that the OEM harness is the way to go! Have not had any more issues. Got one that I pulled from an Avalanche for $20. Wish I had done this in the beginning instead of paying $160 for the BS harness from Just Chevy Trucks.

Theirs look even worse than the one I bought from ls1fans.com and way more expensive. Rip off.

 

[ieastsidechevyrider]

Don't they just deal with used oem parts?

As far as the engines they sell, yes...but the harnesses don’t use any oem parts. Cheap relays and cheap breaker switches (instead of fuses). The breaker switches kept activating, preventing my fans from working, so my car would start to overheat, especially on the hottest days. They may also sell some used oem harnesses, but the majority of the harnesses that they sell are made in-house with cheap parts.


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[RAMurphy]

Thought I would add a post to this thread. I've been running electric fans on my 2002 Tahoe for over 100,000 miles (currently at 251,000). My setup was initially the flexalite fan and controller. About a year after installing I upgraded the controller to the BB harness. All was well until 3 months ago we were on our way to a family vacation on a very hot day (98 degrees +), got stopped in traffic and my temperatures started climbing. I was able to get out of traffic and things cooled back down. However, each time I stopped the temperatures climbed. If you ever installed the flexalite fans, they are quite loud but they move a lot of air. I knew they were not working because I could not hear them. We finally arrived at our mountain cabin and the trouble shooting began. One of the fans stopped working and was pulling a significant amount of amps and blowing my fuses. Luckily I was able to temporarily hotwire the other fan and was able to get home without any problems. Researched a replacement fan using this site and the web and decided to purchase the Dorman 162054. I should have listened to the reviews and this post. Installed this fan and initially very pleased. Much quieter than the flexalites. However, after a day of use, they stopped working. Blew the 40amp fuses. Replaced the fuses after checking the wiring and these fuses blew the next day. Replaced with 50 amp fuses, yep two days later these fuses blew too. Replaced with a resettable 60 amp fuses. These popped too. Checked the amp draw at this point and was surprised to see the draw when these fans kick on high was well over 60 amps. Sent the fan back and ordered the Dorman 162053 fan and have not had a problem since. Maybe I had a bad fan, but based on what I read I think I made the right choice of going with the Dorman 162053. With the 162053 I'm back down around 30amps when fans kick on high. For those concerned about the fans always kicking on and off with the compressor, I wired in a switch in the green wire a/c control signal so I can turn off that input when I'm driving on the highway or when the temperatures outside are low enough where the fan is not required. Works very effectively. I would also recommend an upgraded alternator - I have a 250amp alternator and I do not see any indications when the fans kick on.

 

[Mattn314]

Did the efan swap on my 01. Used factory 05 fans and harness had the comp tuned to run them. Both fans come on when I start the truck cold. Gets to 205 and sits never hotter but fans never go into high.. if I turn the ac the both kick on high. Is this normal operation for them?

 

[Mattn314]

I've had my '02 wired like that as well for 2 years as well without problems, and if the noise of the cycling bothers you all you have to do is turn your blend door selector switch to vent, vent/floor, or floor as long as you don't go past 12 o'clock into floor/defrost or defrost. The cycling at least on my truck only happens on the last 2 selections.

I have a 01 and having issues the fan's come on low as soon as I start up and never goto high and gets to about 195 200.. they come on high when I turn the ac on.. is that how urs works with the swapx

 

[Mattn314]

How-To: Installing 06 E-fans on a 2001

This is a step by step tutorial on how to upgrade any 00-02 Tahoe, Yukon, or Suburban to the 05-06 GMT800 electric cooling fans. This same setup can be used on 03-04 trucks as well, however the only difference is the wiring that connects to the PCM. I will also add that a custom tune from someone like Blackbear Performance(who is a site sponsor by the way) is also needed, because the pins to control the fans in the PCM need to be turned on with the tuning software.

First of all, you need to measure your radiator to see what size it is. Some trucks came with a smaller radiator, (28 inches wide I think) and some have the larger radiator, which is 34 inches wide. The 05-06 Tahoe/Silverado electric fans can only be used if you have the larger radiator. So if you have the smaller one, you need to upgrade your radiator first. If you have the 34 inch radiator, like I do, the fans will bolt right up as if they were made for your truck. The holes for the fan to bolt on are already in the radiator support. It uses the same bolts as the radiator. So if you didn't get the bolts with your new fan, just go grab some radiator bolts off a truck in the junkyard. I got my fans from a 2006 Chevy Silverado in the junkyard. I was also able to pick apart the wiring harness and get that as well. I even got the pin that needs to be added to the PCM harness. So now I have an OEM wiring harness complete with fan relays. This actually clips right onto the side of your underhood fuse panel once you remove the cover. Here is the fans and the harness that I got.
View attachment 116805
View attachment 116806
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View attachment 116809

I cleaned up the harness and added some wire loom to it and made it look cleaner, for a cleaner install.
View attachment 116810
You can buy a pre-made harness from Blackbear Performance for a very easy install. Or if you are able to procure the correct pigtails for the fans and the PCM, you can custom make your own harness. Here is a wiring diagram of how the fans are factory wired on the 05-06 GM trucks.
View attachment 116811
If you have an 03-04 truck, then you will wire it exactly like this diagram shows. But on a 99-02, the PCM only has pin 42 available to use. The other trigger wire has to be connected to the AC compressor clutch relay wire. That wire is positive, so by me using an OEM harness, I had to add a relay to that wire to change it to a negative in order to trigger the fan relay pack, which is set up to be triggered by negative signals from the PCM. This extra relay is not needed if you use the pre-made harness from Blackbear. Thier harness is already setup to use a positive trigger from the AC wire. Now onto the wiring. First you want to remove your underhood fuse panel cover. Not just the lid, the entire cover. You will have to unbolt the corner fender brace in order to get it up and off. Now lift up the fuse junction block to get access to the underside. You will need to splice into the dark green AC clutch relay wire. This is the wire you need.
View attachment 116812
This is where you will tie in your relay (or trigger wire if using a Blackbear harness). The relay needs to be wired as follows:
86-Green AC wire
85-Ground
87-Ground
30-Blue trigger wire on OEM fan relay pack

And here is how your relay should look.
View attachment 116813
View attachment 116814
Now take the green wire on your relay and splice it into the factory Green AC wire with solder and heat shrink tubing.
View attachment 116815
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I grounded the ground wire to this bolt on the fender, right below the fuse block.
View attachment 116819

What relay did u use.. I'm having issues. I used a factory relay 3604

 

[Rocket Man]

What relay did u use.. I'm having issues. I used a factory relay 3604

You should send a PM to @ScottyBoy and ask him questions, he’s pretty much an expert on this.

 

[bottomline2000]

I have a 01 and having issues the fan's come on low as soon as I start up and never goto high and gets to about 195 200.. they come on high when I turn the ac on.. is that how urs works with the swapx

If you have constant fan on you will need to swap to an 0411 pcm. Had this problem on my tahoe. Some early pcm had an operating system that's not compatible and causes the constant fan on and both fans run on high if the ac is running regardless of engine temp. You will burn up relays in wire harness. I swap an 02 Cadillac Escalade into mine. Worked as expected since then.

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[Rocket Man]

If you have constant fan on you will need to swap to an 0411 pcm. Had this problem on my tahoe. Some early pcm had an operating system that's not compatible and causes the constant fan on and both fans run on high if the ac is running regardless of engine temp. You will burn up relays in wire harness. I swap an 02 Cadillac Escalade into mine. Worked as expected since then.

Sent from my SM-T387AA using Tapatalk

Good info, I never heard of this until now.

 

[Mattn314]

If you have constant fan on you will need to swap to an 0411 pcm. Had this problem on my tahoe. Some early pcm had an operating system that's not compatible and causes the constant fan on and both fans run on high if the ac is running regardless of engine temp. You will burn up relays in wire harness. I swap an 02 Cadillac Escalade into mine. Worked as expected since then.

Sent from my SM-T387AA using Tapatalk

Tuner actually finally got it. No fans on till 195 or so then both low then 1 high fan with ac

 

[808_yukon]

Wired mine exactly How yours is but I only get low speed fan when it heats up no ac fan activation

 

[Rocket Man]

Wired mine exactly How yours is but I only get low speed fan when it heats up no ac fan activation

Did you have the pin in the ECM turned on either by a tune or a dealer? It has to be activated or it won’t work via the A/C.

 

[mattbta]

Just for posterity, since this thread gets search hits.

Bolts for fans/radiator PN
11516931