Dash wiring help please

I have a 1972 Plymouth duster 340 that I currently have the dash out of. I have the wiring harness out of it and have gone through a lot of things tracing it and matching it up w/ the schematic from the 72 Dodge Dart-Demon Plymouth Valient-Duster wiring diagram Manual. Problem is that I think the guy I bought the car from had put in a harness from a 73. Most things are the same as on the 72 schematic. I have a few things that I had not been able to trace out so I don't know what they are. I have a question about "what this wire goes to". It goes into some sort of relay under the glove box on the car. The plug has a 3 wire terminal.It is a male plug. one wire is brown w/ a hint of 2 yellow stripes on it. That wire is really long and has been cut off. it is on the top right (plug pointing away from me). Top left is blue w/ white stripe. Bottom one is light grey. Plug up from that is a female plug for same pattern of plug below that but it has a place where it cam mount to the dash on it there are only the grey and blue wires and the other one is blank. I move up to the next level and there is anpther male plug w/ grey bottom, blue w/ white stripe upper left and brown w/ more visible yellow stripes on it. these ones on the upper male plug are in the same position as the ones on the lower plug. Can you please advise me as to what to do there? It almost seems that I should be just hooking up the two brown wires but I am not sure. Here are some pics to help me explain this

anybody?