On a 74. How does it work? I just bought car , had a heavy bag on passenger seat , car wouldn't start,had it towed,started when I got home. Later I realized it must be seat belt relay .should I keep it?if not how best to disable

It's been too many years ago that I disabled mine, but I thought that only disabled the light????

It works off the seat belt receptacle I think. This thread seat belt interlock relay does a good job of explaining how to disable it. Pay close attention to Jeff Bowlsby's pic

There are pressure strips under the seats,easy enough to remove,bypass the relay,take the lamp out of the light its its all disabled,gets rid of unused junk/weight too .