How to test the relays?

 

The relays have a 12 volt coil that when energized closes the contacts on the relay. First check the side of the relay for the diagram outlining the relay function. The using a multi-meter locate the 2 spades that are for the coil. They will show some continuity. The other 2 spades will show open circuit. Apply 12 volts to the coil side then check continuity on the contact side. If the relay is functioning the relay side will show continuity of a complete circuit.