How does one test a relay?
 

I am getting power to one pole of my turn signal relay spade 49 (1979 930) but get no turnsignal illumination. How do I test from here to determine if the relay is functional. Thanks. EP Slick

In the car, you can turn the ignition to on, turn the turnsignal on then remove and reinsert the relay. You should feel it pick up and drop out in your hand. This proves the coil works but does not necessarily mean the contacts aren't bad.

The best way to fully test a relay is to remove it from the car, use a latern battery and put voltage on the coil then use a voltmeter to confirm the resistance changes when the coil is energized. Normally open contacts should change from infinite (high) resistance to zero when the coil is energized. I keep two 6 volt latern batteries on my workbench and wire them in series. However I've found that these relays will work on 6v as well. You could try 6v but the only way to really be sure is to use 12v. Pin connections are shown on the relay.

There should be 12 volts on 49 and 49a with the ignition on before the bi metal strip heats up.

Your problem with the wiper appears to be what got me, the contact in the steering wheel column moves just a little causing the circuit to be interupted. Remove the steering wheel and cover adjust the wiper assembly so it makes contact, you might need a washer for a shim. And you are good to go.

relay
 

Thanks to all. I can manually push the "points" of the relay together but they will not release until I turn ign off. Will continue to fool with but imagine I need new relay. EPS

Another way to test if a relay is bad is to just swap relays and see if the new relay lets the circuit operate correctly.