I just got done hooking up my nelson fan harness. It works great! I've got it hooked up to a toogle switch so I can control them whenever I want and to the a/c. When I turn it on, both fans come on low. Turn the a/c on and the left one turns on high all by itself or if I already them on, the one on the right keeps blowing on low. Just what I wanted. Had a problem with the shipping, but nice product IMO.

 

What brand of fans do you have.

Just asking as the GM Truck (05+) Fans can really abuse a nelson harness (great harness imo) just because of the current draw on startup. And that ends up resulting as constant relay death...

 

thats odd that with the swtich on, and a/c on on full and one half...i have the same kinda tgoggle set up but with switch only, both half...a/c only, one full...a/c and switch, both full....do you not have a both full setting?