I received my contactor in the mail (ZJW 96V/400A), and wanted to give it a little "test", by just putting 12V across the terminals, without plugging it into the controller or anything. I expected to hear or feel the solenoid engage or something, but got nothing at all. Am I doing this right? Does the contactor have to be under load in order to engage? Should I expect to hear / feel anything when I put 12V across the terminals?