Quoted from mark532011:I see that 2 of them were wired with black on one side and 2 are wired with black on the other side.
A coil is symmetrical for electrical purposes, like a resistor, lightbulb, fuse, and other components. As long as black goes to one of the two terminals and the power to activate (switched by a relay) goes to the other side, it doesn't matter which wire goes to which side.
.................David Marston