Under dash to starter wire problem

I had my '74 Dart with a slant six engine, running and starting up without a problem, until last night. I went to mess with the wires under the dash on the driver side of the steering column. Now when I go to start the car the starter does not respond. No clicking or anything. I can stick my hand under the dash and play with the wiring harness and sometimes the starter will click on and start the car. I am guessing there is a wire that goes from that area under the dash to the starter somehow. Does anyone know which wire it is so i can narrow my problem down? Thanks