My 1995 Dodge Ram 2500 Turbo Diesel requires that I depress a yellow button under the hood attached to the turbo charger in order to start the engine. What is the name of this part?

never heard of such a thing, unless its a filter minder thats on the air filter box, which i dont even think they had back in 95.

95's do have a button on the filter box but you don't have to depress it to start the engine and it's to reset the filter when you replace it tells the condition of it

yeah thats just the filter minder it does nothing really