CVR(T) FV103 Spartan in Tracked vehicles Posted July 6, 2020 I would have thought the 3 lights are green for neutral , yellow for over revving, and red for fire indicator. Some of the earlier CVRT engines had a plastic tube around the engine which was pressurised with air and when the engine caught on fire, the tube would melt and the red light would come on telling you that, you had an engine fire! If the air pressure is low the light will come on , with no fire. Later models did away with the air pressure idea, I guess that is what maybe happening ? Cheers.