Hello. I have a '99 Fiat Scudo (1.9TD). It not showing the coolant temperature on the dashboard. When I turn on ignition, the temp gauge goes up and down 3 times. What does it mean? What shuold I check? I already tried it with another temp sensor, but not worked. When I drive the gauge stuck on the minimum temperature.

Looks like that was a simple contact error. I take out the speedometer and after I put it back to its place, the coolant temp gauge started to work.