So far, all i see is a lower reinforcement ground back to fuse box......power window? this from the 71 service manual. I'm doing the wiring on my 71 RR right now and don't see the wire you have. I also have a 71 GTX, but its in storage and tough to get to at the moment. All original wiring in it.



UPDATE:

So I see it as: Lower reinforcement to time delay/low fuel wiring up on the dash as an accessory. Does that ring a bell?

PS, I'm a 71 GTX/RR fan. Please share pics!