To find them, you'll need to look in the engine bay, specifically around the firewall where it meets the engine compartment. They're usually relatively thick rubber hoses and may be connected to metal pipes. One hose will likely be near the thermostat housing, and the other will be somewhere near the water pump or lower intake manifold.
To pinpoint them precisely, I strongly recommend:
* Consulting a repair manual specific to your Cadillac Eldorado's year and engine. These manuals usually have diagrams showing the exact location of all hoses. A Chilton's or Haynes manual would be a good starting point.
* Using an online parts diagram. Many auto parts websites (like AutoZone, Advance Auto Parts, etc.) allow you to select your vehicle's year, make, model, and engine, then view a parts diagram that may show the heater hose locations.
Without knowing the specific year and engine of your Eldorado, giving precise locations is impossible. Attempting to locate them without a visual aid increases the risk of misidentifying other hoses and potentially damaging your vehicle.