I know this has been discussed, but just wanted to give any of you who are a bit leery of wiring your own Ranco a bit of motivation. I did one of my two controllers last night in about an hour, and that was with ****ing up and reversing the wiring (got lucky that I didn't totally jack it up). Seriously, just pay attention to the diagram and visually check it a couple of times before plugging it in.
As for the screw-up, just remember that the LOAD and not the power side is on the left side of the diagram. For some reason, I just assumed left to right and put the connections on the wrong side. Don't let my mistake deter you, if you've ever wired a home or car audio system you can do this.
Right now my chest freezer is at a balmy 40 degrees.
Best Instructions I've found for wiring a Ranco.