This was an issue with the Focus from the same era. It's very likely to be a cracked solder joint inside the cluster. You can send them away to be repaired, but I assume the car wont start without a cluster plugged in, so you'd need to be able to spare the car for a few days. Giving the top of the dash a whack should bring it back on when it goes into 'crazy' mode if it is the cluster.