I know this is an old thread, but I am doing this conversion. I have the fans in, and I have the factory relay block, with about 10" of the harness, and I have the fan side of the harness with the plugs. I need to build the rest, which is not a problem.

The question I have, is about the above pic. What are the two twin small blue wires for? where do they go?

 

They connect up the loom to become one of your signal wires (blue) that goes into the PCM.

 

 

I do have another question I think not asked here.. On 99-02 if you run a relay from the compressor signal wire like the OP did will the fans ever turn off while the compressor is engaged?

Seems the factory 05-06 settings have the fans turn off at 45mph.

 

I have 99 chevy I installed electric fans
I put a pin an the pcm .there I that I have to do the tune

 

I have a problem when I connect the green cable. Electric Fun going on when I turn on the compressor the fan go off when I turn it off la compressor the fans go on

 

IDE connector exactly how is he in the picture but when I do connect the another green cable they work

 

I connect the cable on the PCM that I had to do that tune

 

Hi guys I`m new to the group and have joined because of this post....... I have read this mod and have updated my 03 GMC Sierra 2500 with the dual fans and stock harness from a 05 Chevy….. It drops right in and I had my truck tuned by Pro Car Associates in Akron Ohio by Matt Great guy……My PCM controls the fans and I did add a switch in the cab in case I need to turn them on. It looks great and keeps my truck Cool running around 200. I plow with my truck and it use to run hot on the freeway….. Not anymore thanks to Scott`s write up…….. Great Job Scott. And thank you for sharing….
Fans & Harness $100.00
Tune $150.00
Up Graded Alternator 145 Amp $100.00
Up Graded Alternator Wire 4 Gauge $6.00
Best $350.00 that I have invested in my Truck.

 

For those still on the fence due to the cost of the parts. I just wanted to make everyone aware that I picked up the w/2 day shipping.

I also bought new Chinese E-Fans for $154 a few years back, but a google search indicates there are other options for under $100. The set I bought work fine and fit fine..

The harness/wiring. well you're on your own. I purchased mine from a member here a few years ago, it works great. I just now got everything installed and need to just dial in the settings in EFILive....

Thought I'd pass it along, when this thread was started buying the parts new was almost cost prohibitive IMO, but they've gotten much more reasonable.