w126 blinker slowly stopped working
 

1981 300SD

Sunday morning, blinkers worked fine. Then, later in the afternoon, I go to make a turn, and the blinker would blink a couple of times, then stop. Turn the blinker the other way, same thing. It did this several times, then stopped altogether.

I checked the bulbs in the back, I had a couple that needed to be replaced, so I replaced them. Same problem.

I search the forums and saw a message about cleaning the hazard switch???

Also, how could I tell if the relay is bad? The relays are under the hood where the fuses are and shaped like silver "cubes", right?

What type of troubleshooting could I do?

Thanks.