how to test relay

Apply power; check to see if contacts will pass rated current without significant heaing.

In order to select a relay (or to test it) it helps to know something about how it is going to be used. The metal, shape, and size of the contacts are very different for the applications that use a relay. Very low resistance contacts are used for small signals. Some wipe the contacts together as they close, but most don't. Oxidation of the contact surface adds to the overall circuit resistance. That usually makes things worse, but it may not be important depending on your application.

If the current is too high the contacts will weld together (in which case you have a latched relay.....permanately). A good match of relay contacts to the application will do little if any damage to the contacts. Contact damage is one of the more important items to test. Closing time may be another issue. Your coil type (AC or DC) should be selected for the control signal. Some can handle either, others work best with the type of control signal for which it is designed.

sorry to bump this old thread. I haven seen electricians testing relays with click sound. I am just curious how this works. The way i know is testing continuity