To find it, I strongly suggest you use a repair manual specific to a 1995 Caprice. A Chilton's or Haynes manual will have diagrams and instructions to help you locate and access the valve. Searching online for "1995 Chevrolet Caprice heater control valve location" with images might also provide helpful visual references. Be aware that images might be from slightly different years but the general area will be similar.
Remember to disconnect the battery's negative terminal before starting any work on your vehicle's electrical system.