Remy23

Who makes the best harness to tie into my 2004 Silverado with some LS1 fans? I've found a couple online but wanted to get some opinions.

Thanks

Atomic

iTrader: (42)

I saw some on ebay that looked really good. I used to make harnesses but I cant compete with those and would just buy one if I needed one now.

ezdaar

iTrader: (1)

Oem is best.

Grzmny

Happy with my Nelson performance harness

tpartsman

I went to a you pull yard got the e-fans, e- fan fuse box and traced the two wires through the harness to the pcm. I also got the power wire and grounds. I used a small pick to disconnect the wires from pcm connector(s). Mine looks factory even after adding it on standalone style.

ScottyBoy

iTrader: (4)

OEM harness is best. I actually have an OEM harness for sale. It's a 2006 truck harness with LS1 pigtails soldered on in place of the truck fans pigtails.

RPMSpeed Tech

The nelson provides the best current capacity and higher quality wire and relays and even grounds vs stock.
The biggest issue is normally people dont upgrade the alternator and do not change the tstat at the same time. Most trucks with the fan clutch have the lower output alt. Upgrading that as well as the anemic power cable from the battery junction box helps out significantly.

We will be working on a heavy duty hybrid with upgrades that includes everything needed but is alot cleaner than the nelson harness.

tpartsman

I am running my 105?? amp alternator with e-fans,2 12" subs on a thousand watt amp and added power windows without issues. I did upgrade the thermostat when I planted the V-8 in it I am using the alternator that was on the truck. It maybe higher amps, I never have checked it may have been changed.

RPMSpeed Tech

I added them on all 3 of my 2500hd trucks (2 gmt800s and a gmt900) with 6.0s. 2 of them have manual windows but the gmt900 has the higher output alt stock. They ran fine without much issue until both fans and ac were on then the voltage level would crash and sometimes idle funny too. Even at night you could see the lights dim. Changed to the 140/5 amp alt and no issues since. The voltage is much more consistent and batteries last longer for me. I put all of my trucks through hell from hauling heavy loads to getting stuck in the mud etc. Thats what 3/4 ton trucks are made for though right?
Bumping the idle speed does help also but all my trucks idle at the stock speed (550 - 600).

tpartsman

I failed to mention I have Hid Headlights and foglights. I have seen the gauge drop when fans fire but it goes right back up. I think my alternator has been changed but its a factory not reman. Someone may have put a v-8 alternator on it . I know they bolt on. I also have a badass battery, its ridiculous it was 189.00 800 cca I don't remember but may have a lot to do with it.