The Salar de Pedernales, is located in the commune of Diego de Almagro towards the Cordillera.
They are often confused with the hidden lagoons of Baltinache in San Pedro de Atacama, but these are found in the III region. Getting there is not so easy since they are in the middle of the salt flat, there are no marked paths, you will only see many footprints and yes or if you have to go in a 4x4. That is why I recommend going with someone who knows the area, we went with @geoturismolickanantay and it was an incredible trip!