starter relay-clutch safety switch

1971 duster slant 3 speed manual....... I have New starter relay, it is the one for older 4 speed manual models that did not have the CSS or terminal for NSS. So I am not using the clutch safety switch.... Car will sometimes not get current to the ign switch and with the test light, shows NO current at the yellow ign wire at the Starter relay switch. Now here is the funny part. I can wiggle the large connector under steering column that contains this yellow wire plus all the others (that include the 2 ign 1 wires.) then it starts!!!
I would have to say the problem is an intermittent working starter relay switch, BUT how it is that it will start if I simple wiggle the yellow ( and all wires) at that main connector under the steering column???????