what is this relay called?

The car is a '72 Plymouth Valiant slant 6 with 904 auto trans on the column. Sometimes when I insert the key to start the car, nothing happens UNTIL I jiggle the trans selector back and forth a bit and I hear a clicking sound from a square relay located behind the dash between the ashtray and the glovebox. What is this relay called? As soon as I hear the clicking sound it all is normal and the car starts. Is this a sign of this relay starting to fail or something else in the chain? Thank you very much!