2013 California Standards for Accessible Design Pocket Guide

11B-407.4.7.1.2 Location.

Raised  characters or symbols and Braille designations shall be placed immediately to the left of the control button to which the designations apply.

[2010 ADAS] EXCEPTION:  Where space on an existing car operating panel precludes tactile markings to the left of the controls, markings shall be placed as near to the control as possible.