relay fwd & rev

[Windward]

What is the difference between the fwd and rev on the relays? I have heard that it can be used such that only one spike is needed to acuate a piston. How would we program so we could use one spike?

[radicalnerd]

I think what we did is hook up one side (red wire) of the solenoid to the M+ and the other to the M- then hook up both black wires to ground directly
hope it helps