Remove the two smaller wires from the solenoid. These are the control wires.
Hook a jumper wire from one of those posts to positive on your battery.
using a test light, find power on one of the two larger studs. Then check the opposite large stud, there should be NO power there.
Hook a jumper cable from the other SMALL stud on the relay to ground, or negative, on the battery, if it clicks, then check for power on the large studs. At this point, you should have power on both sides. If not, or if it doesn't click, the relay is no good.