Rocket Man's 02 Denali Build Thread AKA "THE BEAST"

[Rocket Man]

I have no idea how the aftermarket harnesses work but I know the early years (00-02?) have the wrong polarity feed for the OEM harnesses but the afternarket harnesses are pre-wired for the correct polarity for your vehicle. I'm not using an afternarket harness ever again. If you'd like to try one, be my guest! I've messed with this one enough. I've never heard of an OEM one melting. But the afternarkets melt all the time.

 

[adventurenali92]

when I was in the market to buy a GM, I did a lot of reasearch on the GMT800s and which years were the best. On of the biggest reasons I narrowed my search to the 2005 and 2006 trucks was because I wanted the efans. I didn’t want to have to mess with having to try and figure out getting efans installed and all the harnesses when I could get a truck that already had them.

 

[ScottyBoy]

@Rocketman, did this aftermarket fan harness have one single 50a fuse holder? Or was it a 50a fuse for each fan?

 

[Rocket Man]

@Rocketman, did this aftermarket fan harness have one single 50a fuse holder? Or was it a 50a fuse for each fan?

It was originally 2 30 amp regular size blade fuses with normal 20 amp ( I believe) relays and I upgraded it to all 50 amp stuff after it melted the first time. So 2 50 amp fuses.

 

[kbuskill]

I have no idea how the aftermarket harnesses work but I know the early years (00-02?) have the wrong polarity feed for the OEM harnesses but the afternarket harnesses are pre-wired for the correct polarity for your vehicle. I'm not using an afternarket harness ever again. If you'd like to try one, be my guest! I've messed with this one enough. I've never heard of an OEM one melting. But the afternarkets melt all the time.

Ohhh... so you bought that harness pre made... I thought it was something you did yourself... I upgraded my 2000 Esky to the E-fans from an 07+ and never had an issue.

I wired 1 to a thermostatically controlled relay with the probe in the radiator so it would turn on at a preset temperature (adjustable) and I wired the other to a separate relay that was controlled by the A/C compressor.

Worked great and picked up a couple miles per gallon on the old 5.7L.

 

[Rocket Man]

Mines controlled by the ECM like stock. Programmed with the tune.

 

[kbuskill]

Mines controlled by the ECM like stock. Programmed with the tune.

Yeah.. I don't think that was an option on the first gen Esky... at least that I am aware of...

Hopefully the new OEM harness will get you squared away... permanently.

 

[Tonyrodz]

Ohhh... so you bought that harness pre made... I thought it was something you did yourself... I upgraded my 2000 Esky to the E-fans from an 07+ and never had an issue.

I wired 1 to a thermostatically controlled relay with the probe in the radiator so it would turn on at a preset temperature (adjustable) and I wired the other to a separate relay that was controlled by the A/C compressor.

Worked great and picked up a couple miles per gallon on the old 5.7L.

I was thinking about doing it this way on my 03. I have the oem fans and harness.

 

[bottomline2000]

I went back to work last week after nearly 11 months off after my bike accident and of course it happened to be the start of 95-100 degree days that have spanned a week and a half. I'm trying to get used to working out in this stuff, and then on the way home today The Beast overheated. I popped the hood and the e-fans weren't working again so I checked the fuses. A friggin' 50-amp mega fuse was melted but not blown. I mean melted melted. I'm not sure if it's the actual fans that have caused it this time or the relay pack or the damn LS1fans.com harness design. I rebuilt their harness with 50-amp relays, bigger wiring and these mega fuses last summer when the same thing happened. I'll figure it out this weekend when it cools down and I'm not working. I have an OEM harness from @ScottyBoy that I'll install but I want to be sure I don't need a new fan assembly. Looks like I'll be driving The Machine to work for a few days.

View attachment 204437 View attachment 204438

None of the aftermarket harnesses are strong enough. I built my Nelson harness up to 80a mega relays to get it semi stable. It's got to be something to do with the sizing of the wiring and building up too much resistance, but I know the fans can pull a lot of amperage. If mine short out with the a.c. on none of the fans would work. I turn off the a.c. and the coolant temp trigger would let start the fans on low. For the record I never had a problem unless I was running the a.c. and the fans both cycled to high. I kept relays handy and watched the temp gauge constantly.

Ffwd to putting in Scottys harness and we are good even in 110+ deg weather. The relays tuck back under the fuse box next to the firewalI which keeps them out of direct contact with engine bay heat unlike the aftermarket harnesses. I also bought a 2nd set of fans thinking they were the problem and it was the harness the whole time. I have more than $1500 into a damn efan swap but everything works now lol..



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[Rocket Man]

It's done. I didn't take pics, it was hot and I just needed to get it done. Here's a couple after the fact but it all looks like the rest of the OEM stuff. In the first pic, the efan harness is the one running between the radiator hose and battery. Power is coming from that lug with the red tape attached to my 100 amp fuse holder I added for my Big 3. I guess that's the point though. I tested both fans; the a/c function works and I let the engine idle in 90 degree heat until the other fan turned on. It all seems OK but time will tell. I do think it's all in how the harness is built, with the whole assemble away from heat, the type of relays they use, the type of 40 a fuses, the type and size of wire, etc. It's engineered by GM to work on these efans. I sure hope it works in the long haul.