I made mine much more complicated.
Mine was a little bit of a custom project. I had a theory that max cooling would not occur at 100% pump flow at all times. Looked into a variable control method. There is a local electronics shop that puts radio shack to shame as far as parts and expertise. A guy helped me understand a few things and introduced me to Pulse Width Modulation(PWM). You can't just throw a potentiometer inline and dial back the power because you will have a buildup of heat due to resistance. PWM operates by sending an effective signal by pulsing power at 100% and 0%. I wasn't sure if I was up in the night with these ideas, but while searching around on ZZP a few days later, I noticed that they have a variable pump speed controller. I felt validated to read that their unit uses PWM. The ZZP unit takes the signal from the TPS to turn up and down the pump speed. They indicate that they were able to get cooler temps with this method. I was thwarted recently because I had one wire off on my PWM unit, but now that I have it figured out, and bench tested, it's going in tomorrow.
I ran power from the top of the fuse box into a relay that is ignition switched and I also have a manual switch inline.
Mounted my potentiometer on the top of the shifter panel.
Sorry if this was a thread jack.