to test a relay you need a power source and an ohmmeter. You can test the control side of the relay by hooking it to power and groung and listening for the click. If it clicks, the control side is working. Then take your ohmeter and measure across the power side(switch side) of the realy pins. With the relay off the power side of the relay should have infinite resistance, and with the relay on it should have less than five ohms resistance. You can also measure the resistance of the control side of the relay (the coil side). Average resistance of the relay coil should be about 30 ohms.