I was looking at the fans and each one has two terminals. Does it matter which terminal the hot wire goes to and is the other a common or a ground? Does DC even use common wires like AC? If a ground, can I simply hook the ground wires together and find a bolt to ground them to? If a common, do I run them back to the wires off the relay kit or some where else? I'm going to get an electric fan wiring kit, found a nice one a Auto Zone for $27. It has the relay, fuse, wires, etc.. I plan on having one fan on when the engine is on and one switched so I can turn it on & off from inside the cab. Any advice would be appreciated.
Jim

 

Well, the fans are designed to be a "puller" style. Meaning they pull air from the outside into the engine bay. If you wire it backwards, the fans will push instead. Just try them out and swap the wires if you need.

 

What Big Tex said and I used the ground right there on the crossmember below the crank pulley.

Greg