Turn the ignition switch to on to energize the particular circuit you are
testing, if necessary.

Distributor of Quality Electronic Products. Order from Digi-Key®
.

Connect the alligator clip from a test light to any good ground on your
vehicle. Probe the wire coming out of the relay and going to the component with
the tip of the test light. If the bulb in the test light glows, there is
voltage, and your relay is working properly.

Probe the wire or wires feeding voltage to the relay with the test light
following the same procedure used on the previous step. If the light glows,
there is incoming voltage. Otherwise, the relay is not receiving voltage. Check
the voltage source.

Switch the ignition key off. Unplug the relay from its electrical connector,
making sure not to break the locking tabs on the relay.

Identify the relay's power and control terminals. Some relays show a circuit
diagram on top of the case to identify these terminals.

Check for continuity between the two power terminals using an ohmmeter. There
should be no continuity. If there is continuity, replace the
relay.

Connect a jumper wire between the battery positive terminal and one of the
control circuit terminals on the relay. Connect the other control terminal to
ground with another jumper wire. If you do not hear a click as you make the
second connection, reverse the connections. If you still do not hear a click,
replace the relay.

Connect the jumper wires as you did on the previous step. Using an ohmmeter,
check for continuity between the two power terminals. If there is continuity,
the relay is working properly. Otherwise, replace the
relay.