[Mgs] starter relay

[Tuck Southworth]

All,
can someone tell me just exactly what the starter relay does.  And how can I
tell if its not working.
My 70 B will not start despite a new battery, a rebuilt starter and solenoid.
All I get when I turn
the key is a clicking noise which before I replaced it I would have guessed
was a bad solenoid.
I've checked all the wires and connections so I'm thinking it's the relay.

Any thoughts?

Tuck