Santiago is not the friendliest of places for travellers with disabilities, but it’s probably better equipped than most South American capitals. Still, buildings have got little or no facilities for unassisted disabled access and you are likely to rely on porters or staff to help you access them. There have been encouraging signs of change in recent years with the introduction of ramps to most buses and the installation of lifts in Metro stations.
There are a number of association who can provide further guidance on disability issues:

Fondo Nacional de la Discapacidad
Huérfanos 1313 piso 6, Santiago.
Phone: +56 (2) 810 3900

Guia de la Discapacidad

Fundación Teletón
Rosas 1531, Santiago
Phone: + 56 (2) 674 97 00 – + 56 (2) 674 97 05