...wired up a switch on a Nelson Fan Harness to run them manually? if so, how did you do it?

 

I dont know if this will help at all BUT. When i did my 4.8 swap. The harness is not set up for electric fans. SO I had to run two wires (1 to GROUND the low speed fan and 1 to GROUND the high speed fan) Using a 3 way (on off on) switch. IDK how the nelson harness works exactly, but it might have the same general workings.

Dustin

 

I think it would be easier to hookem up so they are used by the pcm. Not sure on his harness but you could do like Dustin said

John

 

I just looked it up:

Low speed cooling fan : Connector C1 Pin 42 D-Grn
High speed cooling fan : Connector c2 Pin 33 D-Blu

I am looking up C1 and C2 colors right now.

I am making it so the computer does all the work.

Dustin

 

have you already purchased the harness?

If not Derek @ edo on ls1tech.com makes the harnesses (just like nelson as far as i know), where there is an ac tap wire, a pcm pin, a pair of relays etc.

He will add two wires to his harness where you connect one to ground and one to a power source and put inlines switches on the wires, prefereable in the cab. No matter what the pcm or the ac is calling for, or even if the truck is off, if you turn one switch on its one fan on high, turn that switch off and the other on, its both on low, and turn both on its both on high. Obviously if both switchs are off it goes back to using the pcm and ac to control the fans. If you have already bought the harness I will go look at my harness (with the wires) and let you know. The harnesss can be bought for around 80 bucks.

 

i already have the nelson harness and the fans hooked up to the pcm. just like having to convience of the manual switch and was wondering if anyone has wired one up to the nelson harness

 

you'll need a 2 prong toggle switch.
you run one side of the switch to a ground and run the other side to the blue wire that taps into the pcm.

 

That will give you both fans on low at your command, with the key on. If you want the fans on high, you can run another switch to the a/c wire. It will need to be 12v, and I guess that you'd probably need a diode also to keep from bringing 12v to the green ac wire in the factory harness...I'm assuming that would turn on the ac magnetic clutch when you don't want it to.

 

search posts by me . . . I did one for Luke03

 

thanks guys