I'm swapping out the stock 85mph gauge cluster on my 87 GN for a NVU setup. After removing the gauge and the backing panel it attaches to, I found a 13 cavity plug on the LH side of the main harness. (The harness that goes up, over and behind the cluster.) The four plugs I removed from LH side of the backing panel for lights, dimmer, twilight sentinel and gauge input all exit the wrapped harness at the same point as this mystery connector. However, I can find no mating plug or module that the13 cavity connector might plug into. I have several other dangling, unplugged connectors under the dash, but as yet I haven't encountered anything on the car that doesn't work. I've only had the car a few months and unfortunately, the buddy I bought it from has dementia so I can't rely on him for advice. I've searched the chassis service manuals but haven't found anything relevant. Any help would be greatly appreciated. Vic