Are you guys hooking these up some way other than an aftermarket relay and temp sensor (fan controler)? Or is there a factory provision on my 2004 HD(doubtful)?

 

Yes, there is actually a factory provision. contact Allen Nelson at Nelson Performance, he can take care of the computer tune and he makes a plug-n-play wiring harness for the swap. do a search for 05 efans and you should find all you need.

 

Yes, he does. I have the plug-&-play harness on my truck. It's awsome!!