Temperature gauge not working

At first, the gauge was working fine. It was, however, reading higher than I would have expected so I thought maybe the thermostat and/or the sensor switch had gone bad. The temperature gauge worked on my way to the repair shop but once they replaced the thermostat and sensor switch the gauge stopped working. The shop owner said they drove the car a little and had a tester hooked up. He said the temperature got to around 195 which I guess is normal and said because his tester was getting readings that meant the sensor switch was working. I got home and the cooling fans were running which, I do not remember them doing much in the past. Did this mean the engine was too hot? Is there another connection between the sensor switch and the dash temperature gauge that could have gone bad/gotten disconnected?