1979 Z28 Camaro, Electric Water Pump

I Recently upgraded to an electric water pump and affixed all the necessary parts to make it fit and run, but now I have a problem.
When I connected the positive and negative wires to the battery from the water pump, it begins to run. Well I thought maybe it needed to run for a little while but it continued to run. The problem is that it runs even when the car is off and no key in the iginition. How can I fix this problem. I thought about running a pos and neg wire to relay switch inside the camaro that way I can turn it off and on when needed or just turn it on when I am about to start the camaro and turn it off when the camaro is off. Can I do this and how would I hook the wires up, just splice into the hot and cold wires and attach them into the switch. Would this work?