I'd also add that my 4JB1 sensors run the gas Trooper gauges perfectly well, which leads me to believe the engine sensors are the same on both engines. Much cheaper for Isuzu this way - wonder what sensors cross over from other Isuzu models? The glow plug sensor is on/off, so maybe look for an electric fan switch from a gas engine?

1988 Isuzu Trooper LS
2.8l Isuzu 4JB1-TC intercooled turbo diesel
www.dieseltrooper.blogspot.com