Where is the thermostat located in a 1997 dodge ram 2500 gas engine?

The thermostat in a 1997 Dodge Ram 2500 with a gas engine is located on the engine, at the rear of the engine block, near where the top radiator hose connects. It's not easily visible without removing some components. You'll likely need to consult a repair manual specific to your engine (e.g., 5.2L, 5.9L, 8.0L) for exact location and removal instructions, as the precise placement can vary slightly depending on the specific engine.