I was wondering if the Nelson fan harness is a one Pin harness?
And if blackbear is the only one that offers a two pin harness?

 

They can make either.


(I just saved you about $50)

 

Ok, well i bought one this week and when i talked to Erica at nelson i asked her if it was a two pin and she looked at the specs and told me i needed pin 42 activated as well as a fan clutch pin or something. So i thought it was the two pin.
But whenever i read about them here i always hear nelson one pin and blackbear two.
So i just wanted to make sure.

 

The 2 pin harness usually refers to 2 pins going into the PCM, while the one that you described sounds like the Nelson 1 pin harness like I have. 1 pin goes to pin 42 of the PCM, while the other goes to the positive lead in the harness by the driver's side head that goes to the compressor clutch. It's a dark green wire IIRC.

 

Ok well if i use that wire that goes to the fan clutch can i pin it for the other pcm pin or do i need another relay?
I was under the impression the two pin harness only needed three relays.

 

The PCM grounds it's pins to activate them, and the popular 1 pin harnesses that are available use a positive trigger for ac fan operation, so you'd have re-wire the harness to make it work. The 1 pin harness utilizes 3 relays, and I believe that the 2 pin does also, as it is activating the fans for the same operation, only using different parameters to turn the fans on. On the 1 pin harness, you get AC fan operation every time the compressor kicks on, while with the 2 pin harness, there are other parameters that have to be met before the AC fan(s) will activate. I believe that the 2 pin set up looks at ac pressures before firing up the fans.

 

Ok so i got my Nelson harness in the mail today and it looked really good all the terminals are sautered and heat shrinked. But it was not the two pin style like i wanted.

So i followed the schematic that Atomic posted and in about fifteen minutes i had it re-worked to work as a two pin. There are not two many differences just two of the wires have to be switched from the ground side to the positive side. And if you use the two black wires that are no longer used for the power side you don't even need any thing extra just re-splice two wires.

so we will see in a few weeks if it works.

 

does anyone have the steps to convert a one ground wire harness to a 2 ground wire harnes??

I'll keep looking at the diagram above

 

I did it using the diagram that Atomic posted. I just took all of the wires off and started over. You end up not having to change much except two wires that were once ground are now to power and the trigger wire needs a PCM pin.

 

So the only difference in the two harness's is that the single pin will kick on the e-fans whenever the AC is turned on, and the double pin turns the fans on when the PCM recognizes pressures created by the compressor? If that's the case, then would the double pin harness turn on the fans at low AC pressures such as at idle, and shut them off at higher pressures such as highway cruising when airflow is sufficient? Which harness is more popular? I'm trying to figure this out, but really have no idea what I'm talking about lol.