Washer pump question

[Mister-B]

I bought a replacement from the junk yard. Turns out it has a stamp on it of 2010, so it's a pretty good score, since it is a replacement. I wired it up and installed it. Prior to hooking up the hoses (since they turned out to be too short and I'll need to buy new ones), I pushed the washer button on the dash and I can see that the motor works and hear it working. The problem is that it comes on and stays on even with just the wipers moving. Why would it be constantly on like that? Ended up just unplugging the power to it, since I don't want to burn it out running every time the wipers are turned on.