I have a 99 Cutlass with the 3.1L engine. Driving home, about 2 weeks ago, I noticed both the temp and fuel gauges stopped working. Everything else on instrument cluster works (ie other gauges, digital odometer, back lights, "idiot lights"). Now my cooling fans are not engaging. Car overheated when I left it running at work for about 10 minutes. Are there some electrical issues causing both problems or just a coincidence they happened within a couple weeks of each other?

 

I would start with the coolant temp sensor. It's not unusual for them to get gummed up and stop working. This would result in loss of the temp signal to the BCM, and no temp readout on the cluster. However, when the BCM can't get a temp signal, it is supposed to turn on the fans just to be safe, so I think you have another problem as well.
Do the fans come on when you turn on the air conditioner? At least one is supposed to.