So im trying to figure out my over heating. Ive got a 2001 2500hd ive converted to efans the nelson performance harness. Does high speed only come on if i have the a/c on? Looks like it will only come on if a/c is on and low speed fan is on? Because i just have the one pcm trigger. And will never go high speed only because of temp?

 

Hmm after some reading maybe i should have gotten the later 2 pin harness instead of the a/c wire harness and flashed the later OS? I just want to make sure both fans will come on high

 

Return the 1 pin harness and get 2 pin harness. Better yet, get an OEM harness.

 

Agreed, get a OEM harness or the two pin at a min.

 

how hard would it be for me to modify this harness? is it the same except the a/c wire gets hooked to hot and the ground for that relay is now for second pcm pin?

 

or maybe i can just make it high speed or not, and just skip the low?

 

Hayden Automotive 3653 Economy Adjustable Thermostatic Fan Control https://www.amazon.com/dp/B000C39C6I..._4lbRvbXXJ26N1


Use this on your high speed AC trigger.