I have a 1996 Ram 2500 with the turbodiesel. When I turn off the engine, the gauges all return to zero- except the pyrometer, which remains at about 300. Is this normal? Or should it return to zero as well? It is an Isspro post exhaust. Any help appreciated.

 

If the gauge has power to keep showing you the actual temp it will. It takes a while for everything to cool back down.