Fan will not turn on

I have a 1990 Celebrity with a 3.1 V6. I had a leak in my radiator, so I switched it out. While checking out where the leak was, one of my friends happened to notice the fan was not turning on. I hadn't noticed it before. So when I picked up a radiator at the wrecking yard, I also picked up a fan. I just hooked it all up, and the fan didn't kick on at all. I know it's buyer beware at a yard, but the odds are pretty steep that I'd get 2 dead fans. So what next? Even my brother was stumped.