1995 C280 Water Temperature Gauge

The water temperature gauge on my wife's 1995 C280 began acting intermittantly yesterday. I checked the connection to the water temperature sending unit and this appears to be OK. I was thinking about replacing the water temperature sending unit next to see if this is the problem. However, before ordering the part, I thought I would check to see if others have encountered this problem and if there is anything else I should check first.