2 speeds with mk viii fan?

[my72vette454]

I have a mark 8 fan and it has 3 terminals on it but the middle terminal doesnt seem to be hooked to anything, how do I get both low and high speeds? Also where can I get a factory plug in for it, I have had problems with the terminals getting hot with those yellow female terminal ends snapped onto them. I have it on a forklift type loader and the fan needs to run all the time for the trans cooler but I think it has enough capacity that low speed might do the trick as if it runs on the thermostat it only stays on for maybe a minute then cycles off for a few.

Mike