Mystery connection on back of instrument cluster

[mckpaul]

Well, pulled the instrument cluster out last night and cleaned it all up and re-lamped it. But don't understand what one of the connections was on the back. On the upper right corner of the cluster housing (when viewing the cluster from the front - in other words, passenger side on the back up high) there was a connection of a black plastic looking cord for lack of a better word. At first I thought it was a small hard plastic tube, then I thought it was a wire since it had a copper sleeve on the end of it and went to it's own special white plastic (or teflon) connector that kind of looked like one of the instrument lamp sockets, but it wouldn't twist out, and had a metal tab holding it in place. But when I got it detached from the cluster it appeared to be nothing more than a solid plastic cord. I followed it to see where it went and it just went to the ash tray housing and connected to the top of that, kind of stubbed into the ashtray bay about 1/16". I put it back like I found it when I finished, but what the heck is this?????