Cluster is only held in by friction fit. No wires to disconnect as all are on self aligning plugs. Lower steering wheel as far as it will go, then disconnect the battery. Remove the knee bolster and push the cluster out from behind. Forget the special tools, as they are difficult to use and can scratch the plastic face plate if you don't get them exactly in the right positions. Failure is probably voltage regulator circuit on cluster, but unless you're a Electronic Engineer, you'll need to send it to one of the repair outfits.
http://mbcluster.com/