If you have a meter, look for the pair of terminals that show a resistance. The other pair will be the load terminals, and should check open. Resistance through the coil may be in the range of 100 - 500 ohms.
If you have not got a meter, you can use clip leads or even wires to make a connection between ground (any part of the car or the battery terminal) and the battery positive terminal. The pair of pins that produce a click from the relay are for the coil.