I just pulled the instrument cluster out for the first time, and there are three black wires which are connected to one common connector, which is pin shaped, about 15-20mm long, and not insulated. The wires appear to go into the console or possibly the air vents above the console. The connector was not plugged in, and I don't see an obvious receptacle for them. I'm guessing they power the lights for the upper bank of switches on the console, since they don't work.

Also, I pulled the cluster to investigate a non working tach and clock. I see a loom with two wires in it that have been taped off. One is black with a red stripe and the other is green with a black stripe. Nothing was plugged into the three prong receptacle on the right side of the cluster (directly behind the tach). Regarding the tach, I have already tried three different sending units (or whatever that round thing with the screw on cover is called on the driver's side of the engine compartment).