Hi new to this but my husband just replaced the water pump and thermostat for my 2000 taurus and now the temperature gauge is not working. could this be a sensor problem- He is not very mechanical and had a lot of help from friends to do this but they don't know why the guage is not working. Thanks for any help.

It may be as simple as it not being connected where the wire was knocked off or it wasn't reconnected after the repair. From there, there's a lot of room for speculation from it was damaged in the process, the wire to it is cut or grounded out...